diff --git a/.github/workflows/sonarcloud.yml b/.github/workflows/sonarcloud.yml
index c29dd12042..97ef982be0 100644
--- a/.github/workflows/sonarcloud.yml
+++ b/.github/workflows/sonarcloud.yml
@@ -18,10 +18,18 @@ jobs:
             sonarProjectKey: reactiveui_ReactiveUI
             sonarOrganization: reactiveui
             sonarExclusions: '**/tests/**,**/integrationtests/**,**/benchmarks/**,**/examples/**,**/TestResults/**'
-            # Shared/Platform fused Rx-replacement observables are compile-linked into every platform assembly and
-            # only exercisable via platform (WPF/WinForms/MAUI/mobile) tests, so exclude them from coverage like
-            # generated code. The Shared/ root helpers stay measured (covered by the core test suite).
-            sonarCoverageExclusions: '**/tests/**,**/integrationtests/**,**/benchmarks/**,**/examples/**,**/*Tests/**,**/*Tests.cs,**/Generated/**,**/Shared/Platform/**'
+            # Coverage exclusions (sonar.coverage.exclusions) — code the Sonar scan cannot execute, so counting it
+            # would only ever report 0%. This is COVERAGE ONLY; every excluded file is still fully analysed for bugs,
+            # smells and duplication.
+            #  - Shared/Platform fused Rx-replacement observables are compile-linked into every platform assembly and
+            #    only exercisable via platform tests; the Shared/ root helpers stay measured (core test suite covers them).
+            #  - The scan runs on windows-latest (see workflow-common-sonarcloud.yml runsOn) so it builds and runs the
+            #    core + WPF + WinUI + WinForms tests — that platform code stays measured (e.g. CreatesWinformsCommandBinding
+            #    sits at ~99%). What it CANNOT run is the android/apple per-OS code under ReactiveUI/Platforms/{android,
+            #    apple-common,ios,mac,tvos,uikit-common,mobile-common}: those need an emulator/device or a mac runner, so
+            #    their tests never execute in CI and the files always read 0%. Exclude exactly those per-OS dirs from
+            #    coverage (Platforms/net and Platforms/netstandard2.0 stay measured — they run under the core tests).
+            sonarCoverageExclusions: '**/tests/**,**/integrationtests/**,**/benchmarks/**,**/examples/**,**/*Tests/**,**/*Tests.cs,**/Generated/**,**/Shared/Platform/**,**/Platforms/android/**,**/Platforms/apple-common/**,**/Platforms/ios/**,**/Platforms/mac/**,**/Platforms/tvos/**,**/Platforms/uikit-common/**,**/Platforms/mobile-common/**'
             # CPD (copy/paste detection) exclusions:
             #  - tests/integrationtests/Benchmarks/examples are non-shipping code. The examples are
             #    demo apps that deliberately parallel each other (each sample reimplements the same
diff --git a/src/Directory.Packages.props b/src/Directory.Packages.props
index 80c46e902a..9d10a8fc8f 100644
--- a/src/Directory.Packages.props
+++ b/src/Directory.Packages.props
@@ -6,7 +6,7 @@
 
   <PropertyGroup Label="Shared Version Variables">
     <SplatVersion>20.0.0</SplatVersion>
-    <PrimitivesVersion>5.6.0</PrimitivesVersion>
+    <PrimitivesVersion>5.7.0</PrimitivesVersion>
     <TUnitVersion>1.56.25</TUnitVersion>
     <XamarinAndroidXLifecycleLiveDataVersion>2.10.0.2</XamarinAndroidXLifecycleLiveDataVersion>
   </PropertyGroup>
diff --git a/src/ReactiveShim.props b/src/ReactiveShim.props
index d6686b587e..309f97291f 100644
--- a/src/ReactiveShim.props
+++ b/src/ReactiveShim.props
@@ -40,6 +40,10 @@
          Broadcaster) resolve unqualified to the lean ReactiveUI.Primitives namespace. Open generics can't be aliased,
          so this is a namespace import rather than a per-type alias like RxVoid/ISequencer above. -->
     <Using Include="ReactiveUI.Primitives.Signals" />
+    <!-- Concrete signal classes (ReturnSignal/StartSignal/ImmutableReturnRxVoidSignal, ...) that back the
+         Signal.* factories. The shared source constructs these directly in place of in-repo sink forks; only
+         the seam-neutral (both-leaf) concretes are named so the .Reactive leaf below stays buildable. -->
+    <Using Include="ReactiveUI.Primitives.Advanced" />
   </ItemGroup>
 
   <!-- Reactive seam: the *.Reactive leaves recompile the shared ReactiveUI source against System.Reactive's
@@ -63,6 +67,9 @@
     <Using Include="ReactiveUI.Reactive.Builder" />
     <Using Include="ReactiveUI.Reactive.Interfaces" />
     <Using Include="ReactiveUI.Primitives.Signals" />
+    <!-- Reactive-shim counterpart of the lean leaf's ReactiveUI.Primitives.Advanced import: the same
+         seam-neutral concrete signal classes, flipped to the ReactiveUI.Primitives.Reactive.Advanced namespace. -->
+    <Using Include="ReactiveUI.Primitives.Reactive.Advanced" />
   </ItemGroup>
 
   <!-- Reactive seam, platform leaves: the apple/android reactive main-thread sequencers
diff --git a/src/ReactiveUI.Core/Internal/SingleValueObservable{T}.cs b/src/ReactiveUI.Core/Internal/SingleValueObservable{T}.cs
deleted file mode 100644
index 536829d109..0000000000
--- a/src/ReactiveUI.Core/Internal/SingleValueObservable{T}.cs
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright (c) 2009-2026 .NET Foundation and Contributors. All rights reserved.
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for full license information.
-
-using ReactiveUI.Primitives.Disposables;
-
-namespace ReactiveUI.Internal;
-
-/// <summary>
-/// A cold observable that emits a single value and then completes on each subscription.
-/// Replaces <c>Observable.Return</c> for internal use.
-/// </summary>
-/// <typeparam name="T">The element type.</typeparam>
-/// <param name="value">The value emitted to each subscriber.</param>
-public sealed class SingleValueObservable<T>(T value) : IObservable<T>
-{
-    /// <inheritdoc/>
-    public IDisposable Subscribe(IObserver<T> observer)
-    {
-        ArgumentExceptionHelper.ThrowIfNull(observer);
-        observer.OnNext(value);
-        observer.OnCompleted();
-        return EmptyDisposable.Instance;
-    }
-}
diff --git a/src/ReactiveUI.Core/Internal/SyncExecuteObservable.cs b/src/ReactiveUI.Core/Internal/SyncExecuteObservable.cs
deleted file mode 100644
index f1d10e7506..0000000000
--- a/src/ReactiveUI.Core/Internal/SyncExecuteObservable.cs
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright (c) 2009-2026 .NET Foundation and Contributors. All rights reserved.
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for full license information.
-
-using ReactiveUI.Primitives.Disposables;
-
-namespace ReactiveUI.Internal;
-
-/// <summary>
-/// Runs a function synchronously on each subscription, then emits its result and completes.
-/// A fault in the function is forwarded as an error. Backs the synchronous command factories.
-/// </summary>
-/// <typeparam name="T">The result type.</typeparam>
-/// <param name="execute">The function to run on subscription.</param>
-public sealed class SyncExecuteObservable<T>(Func<T> execute) : IObservable<T>
-{
-    /// <inheritdoc/>
-    public IDisposable Subscribe(IObserver<T> observer)
-    {
-        ArgumentExceptionHelper.ThrowIfNull(observer);
-        try
-        {
-            var result = execute();
-            observer.OnNext(result);
-            observer.OnCompleted();
-        }
-        catch (Exception ex)
-        {
-            observer.OnError(ex);
-        }
-
-        return EmptyDisposable.Instance;
-    }
-}
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0-android36.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0-android36.0/PublicAPI.Shipped.txt
index e345d49012..0167082cde 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0-android36.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0-android36.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0-ios/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0-ios/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0-ios/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0-ios/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0-maccatalyst/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0-maccatalyst/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0-maccatalyst/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0-maccatalyst/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0-macos/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0-macos/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0-macos/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0-macos/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0-tvos/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0-tvos/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0-tvos/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0-tvos/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0-windows10.0.19041.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0-windows10.0.19041.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0-windows10.0.19041.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0-windows10.0.19041.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net10.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net10.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net10.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net10.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0-android37/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0-android37/PublicAPI.Shipped.txt
index e345d49012..0167082cde 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0-android37/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0-android37/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0-ios/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0-ios/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0-ios/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0-ios/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0-maccatalyst/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0-maccatalyst/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0-maccatalyst/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0-maccatalyst/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0-macos/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0-macos/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0-macos/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0-macos/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0-tvos/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0-tvos/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0-tvos/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0-tvos/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0-windows10.0.19041.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0-windows10.0.19041.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0-windows10.0.19041.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0-windows10.0.19041.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net11.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net11.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net11.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net11.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net462/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net462/PublicAPI.Shipped.txt
index 68a754a7c4..8bc5ad247b 100644
--- a/src/ReactiveUI.Core/PublicAPI/net462/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net462/PublicAPI.Shipped.txt
@@ -317,15 +317,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net472/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net472/PublicAPI.Shipped.txt
index 68a754a7c4..8bc5ad247b 100644
--- a/src/ReactiveUI.Core/PublicAPI/net472/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net472/PublicAPI.Shipped.txt
@@ -317,15 +317,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net481/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net481/PublicAPI.Shipped.txt
index 68a754a7c4..8bc5ad247b 100644
--- a/src/ReactiveUI.Core/PublicAPI/net481/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net481/PublicAPI.Shipped.txt
@@ -317,15 +317,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net8.0-windows10.0.19041.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net8.0-windows10.0.19041.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net8.0-windows10.0.19041.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net8.0-windows10.0.19041.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net8.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net8.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net8.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net8.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net9.0-windows10.0.19041.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net9.0-windows10.0.19041.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net9.0-windows10.0.19041.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net9.0-windows10.0.19041.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Core/PublicAPI/net9.0/PublicAPI.Shipped.txt b/src/ReactiveUI.Core/PublicAPI/net9.0/PublicAPI.Shipped.txt
index 88a41d7dc6..b7bb18767d 100644
--- a/src/ReactiveUI.Core/PublicAPI/net9.0/PublicAPI.Shipped.txt
+++ b/src/ReactiveUI.Core/PublicAPI/net9.0/PublicAPI.Shipped.txt
@@ -319,15 +319,9 @@ ReactiveUI.InteractionContext<TInput, TOutput>.Input.get -> TInput
 ReactiveUI.InteractionContext<TInput, TOutput>.InteractionContext(TInput input) -> void
 ReactiveUI.InteractionContext<TInput, TOutput>.IsHandled.get -> bool
 ReactiveUI.InteractionContext<TInput, TOutput>.SetOutput(TOutput output) -> void
-ReactiveUI.Internal.SingleValueObservable<T>
-ReactiveUI.Internal.SingleValueObservable<T>.SingleValueObservable(T value) -> void
-ReactiveUI.Internal.SingleValueObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.StartWithObservable<T>
 ReactiveUI.Internal.StartWithObservable<T>.StartWithObservable(System.IObservable<T>! source, T value) -> void
 ReactiveUI.Internal.StartWithObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>
-ReactiveUI.Internal.SyncExecuteObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
-ReactiveUI.Internal.SyncExecuteObservable<T>.SyncExecuteObservable(System.Func<T>! execute) -> void
 ReactiveUI.Internal.TaskObservable<T>
 ReactiveUI.Internal.TaskObservable<T>.Subscribe(System.IObserver<T>! observer) -> System.IDisposable!
 ReactiveUI.Internal.TaskObservable<T>.TaskObservable(System.Threading.Tasks.Task<T>! task) -> void
diff --git a/src/ReactiveUI.Maui/RoutedViewHost.cs b/src/ReactiveUI.Maui/RoutedViewHost.cs
index 1571dd8b34..edc1c6dc00 100644
--- a/src/ReactiveUI.Maui/RoutedViewHost.cs
+++ b/src/ReactiveUI.Maui/RoutedViewHost.cs
@@ -64,18 +64,11 @@ public RoutedViewHost()
         SubscribeToPopped();
         SubscribeToPoppedToRoot();
 
-        // Perform initial sync asynchronously
-        _ = Task.Run(async () =>
-        {
-            try
-            {
-                await SyncNavigationStacksAsync();
-            }
-            catch (Exception ex)
-            {
-                this.Log().Error(ex, "Failed to perform initial navigation stack sync");
-            }
-        });
+        // Perform the initial navigation-stack sync on the main thread rather than a thread-pool thread. MAUI
+        // navigation state must only be mutated from the UI thread, and marshalling here serialises the initial
+        // sync with any subsequent navigation instead of racing it on a background thread (the previous Task.Run
+        // could interleave its own PushAsync with a caller's push and leave CurrentPage pointing at the wrong page).
+        _ = RxSchedulers.MainThreadScheduler.Schedule(() => _ = PerformInitialNavigationSyncAsync());
     }
 
     /// <summary>Gets or sets the <see cref="RoutingState"/> of the view model stack.</summary>
@@ -225,6 +218,25 @@ protected async Task SyncNavigationStacksAsync()
         }
     }
 
+    /// <summary>Performs the one-time initial navigation-stack sync, logging any failure instead of faulting an unobserved task.</summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [RequiresUnreferencedCode(
+        "This method uses reflection to determine the view model type at runtime, which may be incompatible with trimming.")]
+    [RequiresDynamicCode(
+        "If some of the generic arguments are annotated (either with DynamicallyAccessedMembersAttribute, or generic constraints), " +
+        "trimming can't validate that the requirements of those annotations are met.")]
+    private async Task PerformInitialNavigationSyncAsync()
+    {
+        try
+        {
+            await SyncNavigationStacksAsync();
+        }
+        catch (Exception ex)
+        {
+            this.Log().Error(ex, "Failed to perform initial navigation stack sync");
+        }
+    }
+
     /// <summary>Subscribes to <see cref="RoutingState.NavigationStack"/> changes and resyncs when the stack is cleared.</summary>
     [RequiresUnreferencedCode(
         "This method uses reflection to determine the view model type at runtime, which may be incompatible with trimming.")]
diff --git a/src/ReactiveUI.Shared/Activation/CanActivateViewFetcher.cs b/src/ReactiveUI.Shared/Activation/CanActivateViewFetcher.cs
index 1851f524a3..02d6e0e36a 100644
--- a/src/ReactiveUI.Shared/Activation/CanActivateViewFetcher.cs
+++ b/src/ReactiveUI.Shared/Activation/CanActivateViewFetcher.cs
@@ -36,7 +36,7 @@ public int GetAffinityForView(Type view) =>
     /// <see langword="false"/> when it is deactivated.</returns>
     public IObservable<bool> GetActivationForView(IActivatableView view) =>
         view is not ICanActivate canActivate
-            ? SingleValueObservable.False
+            ? new ReturnSignal<bool>(false, Sequencer.Immediate)
             : new ActivationStateObservable(canActivate.Activated, canActivate.Deactivated);
 
     /// <summary>
diff --git a/src/ReactiveUI.Shared/Bindings/Property/PropertyBinderImplementation.cs b/src/ReactiveUI.Shared/Bindings/Property/PropertyBinderImplementation.cs
index acd6451fba..c1ccea9b3c 100644
--- a/src/ReactiveUI.Shared/Bindings/Property/PropertyBinderImplementation.cs
+++ b/src/ReactiveUI.Shared/Bindings/Property/PropertyBinderImplementation.cs
@@ -554,7 +554,7 @@ public IDisposable BindTo<TValue, TTarget, TTargetValue>(
     /// <returns>An observable that emits <paramref name="value"/> when the binding should continue.</returns>
     protected virtual IObservable<bool> ScheduleForBinding<TView>(TView view, bool value)
         where TView : class =>
-        new SingleValueObservable<bool>(value);
+        new ReturnSignal<bool>(value, Sequencer.Immediate);
 
     /// <summary>
     /// Applies a view-value setter. The default invokes it inline; platform binders (e.g. WPF) override this to
diff --git a/src/ReactiveUI.Shared/Interactions/Interaction.cs b/src/ReactiveUI.Shared/Interactions/Interaction.cs
index 92b7d1873e..2e5c3e6677 100644
--- a/src/ReactiveUI.Shared/Interactions/Interaction.cs
+++ b/src/ReactiveUI.Shared/Interactions/Interaction.cs
@@ -107,7 +107,7 @@ public IDisposable RegisterHandler(Action<IInteractionContext<TInput, TOutput>>
         IObservable<RxVoid> ContentHandler(IInteractionContext<TInput, TOutput> interaction)
         {
             handler(interaction);
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
     }
 
diff --git a/src/ReactiveUI.Shared/Internal/SingleValueObservable.cs b/src/ReactiveUI.Shared/Internal/SingleValueObservable.cs
deleted file mode 100644
index 6846e44aca..0000000000
--- a/src/ReactiveUI.Shared/Internal/SingleValueObservable.cs
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright (c) 2009-2026 .NET Foundation and Contributors. All rights reserved.
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for full license information.
-
-#if REACTIVE_SHIM
-namespace ReactiveUI.Reactive.Internal;
-#else
-namespace ReactiveUI.Internal;
-#endif
-/// <summary>
-/// Provides pre-allocated <see cref="SingleValueObservable{T}"/> singletons for values emitted often enough to be
-/// worth sharing rather than re-allocating on each use.
-/// </summary>
-internal static class SingleValueObservable
-{
-    /// <summary>
-    /// A shared cold observable that emits <see cref="RxVoid.Default"/> once and then completes. Reused to avoid the
-    /// allocation of a fresh <see cref="SingleValueObservable{T}"/> for the very common "completed unit" case.
-    /// </summary>
-    public static readonly IObservable<RxVoid> Void = new SingleValueObservable<RxVoid>(RxVoid.Default);
-
-    /// <summary>A shared cold observable that emits a single <c>true</c> and then completes.</summary>
-    public static readonly IObservable<bool> True = new SingleValueObservable<bool>(true);
-
-    /// <summary>A shared cold observable that emits a single <c>false</c> and then completes.</summary>
-    public static readonly IObservable<bool> False = new SingleValueObservable<bool>(false);
-}
diff --git a/src/ReactiveUI.Shared/Internal/StartObservable.cs b/src/ReactiveUI.Shared/Internal/StartObservable.cs
deleted file mode 100644
index 490ca34727..0000000000
--- a/src/ReactiveUI.Shared/Internal/StartObservable.cs
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright (c) 2009-2026 .NET Foundation and Contributors. All rights reserved.
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for full license information.
-
-using ReactiveUI.Primitives.Disposables;
-
-#if REACTIVE_SHIM
-namespace ReactiveUI.Reactive.Internal;
-#else
-namespace ReactiveUI.Internal;
-#endif
-/// <summary>
-/// Runs a function on a scheduler when subscribed, then emits its result and completes.
-/// Replaces <c>Observable.Start</c> for internal use.
-/// </summary>
-/// <typeparam name="T">The result type.</typeparam>
-/// <param name="function">The function to run on the scheduler.</param>
-/// <param name="scheduler">The scheduler the function runs on.</param>
-internal sealed class StartObservable<T>(Func<T> function, ISequencer scheduler) : IObservable<T>
-{
-    /// <inheritdoc/>
-    public IDisposable Subscribe(IObserver<T> observer)
-    {
-        ArgumentExceptionHelper.ThrowIfNull(observer);
-        return scheduler.ScheduleOrInline(
-            (Function: function, Observer: observer),
-            static (_, state) =>
-            {
-                try
-                {
-                    var result = state.Function();
-                    state.Observer.OnNext(result);
-                    state.Observer.OnCompleted();
-                }
-                catch (Exception ex)
-                {
-                    state.Observer.OnError(ex);
-                }
-
-                return EmptyDisposable.Instance;
-            });
-    }
-}
diff --git a/src/ReactiveUI.Shared/Mixins/ObservableLoggingMixins.cs b/src/ReactiveUI.Shared/Mixins/ObservableLoggingMixins.cs
index f0e8d8d330..6fc2ae3232 100644
--- a/src/ReactiveUI.Shared/Mixins/ObservableLoggingMixins.cs
+++ b/src/ReactiveUI.Shared/Mixins/ObservableLoggingMixins.cs
@@ -113,7 +113,7 @@ public IObservable<T> LoggedCatch<TObj>(
             string? message)
             where TObj : IEnableLogger
         {
-            next ??= new SingleValueObservable<T>(default!);
+            next ??= new ReturnSignal<T>(default!, Sequencer.Immediate);
             return new LoggedCatchObservable<T, Exception>(@this, ex =>
             {
                 @class.Log().Warn(ex, message ?? string.Empty);
diff --git a/src/ReactiveUI.Shared/ReactiveCommand/CombinedReactiveCommand.cs b/src/ReactiveUI.Shared/ReactiveCommand/CombinedReactiveCommand.cs
index 3344ffec3e..3272aa007c 100644
--- a/src/ReactiveUI.Shared/ReactiveCommand/CombinedReactiveCommand.cs
+++ b/src/ReactiveUI.Shared/ReactiveCommand/CombinedReactiveCommand.cs
@@ -94,7 +94,7 @@ protected internal CombinedReactiveCommand(
             childCanExecute[i] = childCommandsArray[i].CanExecute;
         }
 
-        var parentGate = canExecute ?? SingleValueObservable.True;
+        var parentGate = canExecute ?? new ReturnSignal<bool>(true, Sequencer.Immediate);
 
         // all-true of [parent, child0..childN] (the parent gate plus every child's CanExecute).
         var canExecuteSources = new IObservable<bool>[childCommandsArray.Length + 1];
diff --git a/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand.cs b/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand.cs
index 5aadc22445..4b3443fa29 100644
--- a/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand.cs
+++ b/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand.cs
@@ -103,11 +103,13 @@ public static ReactiveCommand<RxVoid, RxVoid> Create(
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return new(
-            _ => new SyncExecuteObservable<RxVoid>(() =>
-            {
-                execute();
-                return RxVoid.Default;
-            }),
+            _ => new StartSignal<RxVoid>(
+                () =>
+                {
+                    execute();
+                    return RxVoid.Default;
+                },
+                Sequencer.Immediate),
             canExecute,
             outputScheduler);
     }
@@ -159,7 +161,7 @@ public static ReactiveCommand<RxVoid, TResult> Create<TResult>(
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return new(
-            _ => new SyncExecuteObservable<TResult>(execute),
+            _ => new StartSignal<TResult>(execute, Sequencer.Immediate),
             canExecute,
             outputScheduler);
     }
@@ -211,11 +213,13 @@ public static ReactiveCommand<TParam, RxVoid> Create<TParam>(
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return new(
-            param => new SyncExecuteObservable<RxVoid>(() =>
-            {
-                execute(param);
-                return RxVoid.Default;
-            }),
+            param => new StartSignal<RxVoid>(
+                () =>
+                {
+                    execute(param);
+                    return RxVoid.Default;
+                },
+                Sequencer.Immediate),
             canExecute,
             outputScheduler);
     }
@@ -277,7 +281,7 @@ public static ReactiveCommand<TParam, TResult> Create<TParam, TResult>(
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return new(
-            param => new SyncExecuteObservable<TResult>(() => execute(param)),
+            param => new StartSignal<TResult>(() => execute(param), Sequencer.Immediate),
             canExecute,
             outputScheduler);
     }
@@ -341,7 +345,7 @@ public static ReactiveCommand<RxVoid, RxVoid> CreateRunInBackground(
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return CreateFromObservable(
-            () => new StartObservable<RxVoid>(
+            () => new StartSignal<RxVoid>(
                 () =>
                 {
                     execute();
@@ -424,7 +428,7 @@ public static ReactiveCommand<RxVoid, TResult> CreateRunInBackground<TResult>(
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return CreateFromObservable(
-            () => new StartObservable<TResult>(execute, backgroundScheduler ?? RxSchedulers.TaskpoolScheduler),
+            () => new StartSignal<TResult>(execute, backgroundScheduler ?? RxSchedulers.TaskpoolScheduler),
             canExecute,
             outputScheduler);
     }
@@ -494,7 +498,7 @@ public static ReactiveCommand<TParam, RxVoid> CreateRunInBackground<TParam>(
 
         return CreateFromObservable<TParam, RxVoid>(
             p =>
-                new StartObservable<RxVoid>(
+                new StartSignal<RxVoid>(
                     () =>
                     {
                         execute(p);
@@ -582,7 +586,7 @@ public static ReactiveCommand<TParam, TResult> CreateRunInBackground<TParam, TRe
         ArgumentExceptionHelper.ThrowIfNull(execute);
 
         return CreateFromObservable<TParam, TResult>(
-            p => new StartObservable<TResult>(() => execute(p), backgroundScheduler ?? RxSchedulers.TaskpoolScheduler),
+            p => new StartSignal<TResult>(() => execute(p), backgroundScheduler ?? RxSchedulers.TaskpoolScheduler),
             canExecute,
             outputScheduler);
     }
diff --git a/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand{TParam,TResult}.cs b/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand{TParam,TResult}.cs
index ffb9dc26ca..153564e1f2 100644
--- a/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand{TParam,TResult}.cs
+++ b/src/ReactiveUI.Shared/ReactiveCommand/ReactiveCommand{TParam,TResult}.cs
@@ -91,7 +91,7 @@ protected internal ReactiveCommand(
         CanExecute = new BoolStream(this, isExecuting: false);
         IsExecuting = new BoolStream(this, isExecuting: true);
         ThrownExceptions = new ExceptionStream(this);
-        _canExecuteSubscription = (canExecute ?? SingleValueObservable.True)
+        _canExecuteSubscription = (canExecute ?? new ReturnSignal<bool>(true, Sequencer.Immediate))
             .Subscribe(new DelegateObserver<bool>(OnUserCanExecute, OnUserCanExecuteError));
     }
 
@@ -105,7 +105,7 @@ protected internal ReactiveCommand(
         IObservable<bool>? canExecute,
         ISequencer? outputScheduler)
         : this(
-            p => new SingleValueObservable<(IObservable<TResult> Result, Action Cancel)>((execute(p), NoCancel)),
+            p => new ReturnSignal<(IObservable<TResult> Result, Action Cancel)>((execute(p), NoCancel), Sequencer.Immediate),
             canExecute,
             outputScheduler)
     {
diff --git a/src/ReactiveUI.Shared/Routing/RoutingState.cs b/src/ReactiveUI.Shared/Routing/RoutingState.cs
index b2d9f73f10..2bcaa29a2a 100644
--- a/src/ReactiveUI.Shared/Routing/RoutingState.cs
+++ b/src/ReactiveUI.Shared/Routing/RoutingState.cs
@@ -192,7 +192,7 @@ private sealed class ScheduledValueObservable<T>(T value, ISequencer scheduler)
         public IDisposable Subscribe(IObserver<T> observer)
         {
             ArgumentExceptionHelper.ThrowIfNull(observer);
-            return new SingleValueObservable<T>(value).Subscribe(new SchedulingObserver<T>(observer, scheduler));
+            return new ReturnSignal<T>(value, Sequencer.Immediate).Subscribe(new SchedulingObserver<T>(observer, scheduler));
         }
     }
 
diff --git a/src/ReactiveUI.Shared/Suspension/DummySuspensionDriver.cs b/src/ReactiveUI.Shared/Suspension/DummySuspensionDriver.cs
index 22e455e558..8c467467b1 100644
--- a/src/ReactiveUI.Shared/Suspension/DummySuspensionDriver.cs
+++ b/src/ReactiveUI.Shared/Suspension/DummySuspensionDriver.cs
@@ -28,10 +28,10 @@ public sealed class DummySuspensionDriver : ISuspensionDriver
         "Implementations commonly use reflection-based serialization. " +
         "Prefer LoadState<T>(JsonTypeInfo<T>) for trimming or AOT scenarios.")]
     public IObservable<object?> LoadState()
-        => new SingleValueObservable<object?>(null);
+        => new ReturnSignal<object?>(null, Sequencer.Immediate);
 
     /// <inheritdoc />
-    public IObservable<T?> LoadState<T>(JsonTypeInfo<T> typeInfo) => new SingleValueObservable<T?>(default);
+    public IObservable<T?> LoadState<T>(JsonTypeInfo<T> typeInfo) => new ReturnSignal<T?>(default, Sequencer.Immediate);
 
     /// <inheritdoc />
     [RequiresUnreferencedCode(
@@ -41,12 +41,12 @@ public sealed class DummySuspensionDriver : ISuspensionDriver
         "Implementations commonly use reflection-based serialization. " +
         "Prefer SaveState<T>(T, JsonTypeInfo<T>) for trimming or AOT scenarios.")]
     public IObservable<RxVoid> SaveState<T>(T state)
-        => SingleValueObservable.Void;
+        => ImmutableReturnRxVoidSignal.Instance;
 
     /// <inheritdoc />
-    public IObservable<RxVoid> SaveState<T>(T state, JsonTypeInfo<T> typeInfo) => SingleValueObservable.Void;
+    public IObservable<RxVoid> SaveState<T>(T state, JsonTypeInfo<T> typeInfo) => ImmutableReturnRxVoidSignal.Instance;
 
     /// <inheritdoc />
     public IObservable<RxVoid> InvalidateState()
-        => SingleValueObservable.Void;
+        => ImmutableReturnRxVoidSignal.Instance;
 }
diff --git a/src/ReactiveUI.Shared/Suspension/SuspensionHostExtensions.cs b/src/ReactiveUI.Shared/Suspension/SuspensionHostExtensions.cs
index 8a47cdbab7..f3b58c6239 100644
--- a/src/ReactiveUI.Shared/Suspension/SuspensionHostExtensions.cs
+++ b/src/ReactiveUI.Shared/Suspension/SuspensionHostExtensions.cs
@@ -23,6 +23,10 @@ namespace ReactiveUI;
 /// </remarks>
 public static class SuspensionHostExtensions
 {
+    /// <summary>A shared completed RxVoid signal. Typed as the interface so the synchronous helpers below
+    /// surface it without CA1859 demanding the concrete singleton type leak into their signatures.</summary>
+    private static readonly IObservable<RxVoid> _completed = ImmutableReturnRxVoidSignal.Instance;
+
     /// <summary>Func used to load app state exactly once. Backing field for testing purposes.</summary>
     private static Func<IObservable<RxVoid>>? _ensureLoadAppStateFunc;
 
@@ -305,7 +309,7 @@ private static IObservable<RxVoid> EnsureLoadAppState(ISuspensionHost item, ISus
     {
         if (item.AppState is not null)
         {
-            return SingleValueObservable.Void;
+            return _completed;
         }
 
         _suspensionDriver ??= driver ?? AppLocator.Current.GetService<ISuspensionDriver>();
@@ -313,7 +317,7 @@ private static IObservable<RxVoid> EnsureLoadAppState(ISuspensionHost item, ISus
         if (_suspensionDriver is null)
         {
             item.Log().Error("Could not find a valid driver and therefore cannot load app state.");
-            return SingleValueObservable.Void;
+            return _completed;
         }
 
         try
@@ -327,7 +331,7 @@ private static IObservable<RxVoid> EnsureLoadAppState(ISuspensionHost item, ISus
             item.AppState = item.CreateNewAppState?.Invoke();
         }
 
-        return SingleValueObservable.Void;
+        return _completed;
     }
 
     /// <summary>Ensures a one-time typed app state load from storage using source-generated JSON metadata (trimming/AOT friendly).</summary>
@@ -344,7 +348,7 @@ private static IObservable<RxVoid> EnsureLoadAppState<TAppState>(
     {
         if (item.AppStateValue is not null)
         {
-            return SingleValueObservable.Void;
+            return _completed;
         }
 
         _suspensionDriver ??= driver ?? AppLocator.Current.GetService<ISuspensionDriver>();
@@ -352,7 +356,7 @@ private static IObservable<RxVoid> EnsureLoadAppState<TAppState>(
         if (_suspensionDriver is null)
         {
             item.Log().Error("Could not find a valid driver and therefore cannot load app state.");
-            return SingleValueObservable.Void;
+            return _completed;
         }
 
         try
@@ -366,7 +370,7 @@ private static IObservable<RxVoid> EnsureLoadAppState<TAppState>(
             item.AppStateValue = item.CreateNewAppStateTyped?.Invoke();
         }
 
-        return SingleValueObservable.Void;
+        return _completed;
     }
 
     /// <summary>Runs the pending one-time app-state load exactly once, if one is registered.</summary>
diff --git a/src/ReactiveUI.Winforms/CreatesWinformsCommandBinding.cs b/src/ReactiveUI.Winforms/CreatesWinformsCommandBinding.cs
index b9ea756f6d..aa19b8a57e 100644
--- a/src/ReactiveUI.Winforms/CreatesWinformsCommandBinding.cs
+++ b/src/ReactiveUI.Winforms/CreatesWinformsCommandBinding.cs
@@ -239,53 +239,14 @@ public IDisposable? BindCommandToObject<
         ArgumentExceptionHelper.ThrowIfNull(addHandler);
         ArgumentExceptionHelper.ThrowIfNull(removeHandler);
 
-        if (command is null)
-        {
-            return EmptyDisposable.Instance;
-        }
-
-        object? latestParameter = null;
-
-        void Handler(object? s, TEventArgs e)
-        {
-            var param = Volatile.Read(ref latestParameter);
-            if (!command.CanExecute(param))
+        return command is null
+            ? EmptyDisposable.Instance
+            : BindToHandler(command, target, typeof(T), commandParameter, execute =>
             {
-                return;
-            }
-
-            command.Execute(param);
-        }
-
-        var ret = new MultipleDisposable { commandParameter.Subscribe(new DelegateObserver<object?>(x => Volatile.Write(ref latestParameter, x))) };
-
-        addHandler(Handler);
-        ret.Add(new ActionDisposable(() => removeHandler(Handler)));
-
-        // Handle Enabled property binding for Components
-        var targetType = typeof(T);
-        if (typeof(Component).IsAssignableFrom(targetType))
-        {
-            var enabledProperty = targetType.GetRuntimeProperty("Enabled");
-
-            if (enabledProperty is null)
-            {
-                return ret;
-            }
-
-            // Replaces FromEvent(CanExecuteChanged).StartWith(initial).Subscribe(...).
-            var canExecuteChanged = new FromEventObservable<bool>(onNext =>
-            {
-                void CanExecuteHandler(object? sender, EventArgs e) => onNext(command.CanExecute(Volatile.Read(ref latestParameter)));
-                command.CanExecuteChanged += CanExecuteHandler;
-                return new ActionDisposable(() => command.CanExecuteChanged -= CanExecuteHandler);
+                void Handler(object? s, TEventArgs e) => execute();
+                addHandler(Handler);
+                return new ActionDisposable(() => removeHandler(Handler));
             });
-
-            ret.Add(new StartWithObservable<bool>(canExecuteChanged, command.CanExecute(latestParameter))
-                .Subscribe(new DelegateObserver<bool>(x => enabledProperty.SetValue(target, x, null))));
-        }
-
-        return ret;
     }
 
     /// <summary>
@@ -316,14 +277,40 @@ public IDisposable? BindCommandToObject<
         ArgumentExceptionHelper.ThrowIfNull(addHandler);
         ArgumentExceptionHelper.ThrowIfNull(removeHandler);
 
-        if (command is null)
-        {
-            return EmptyDisposable.Instance;
-        }
+        return command is null
+            ? EmptyDisposable.Instance
+            : BindToHandler(command, target, typeof(T), commandParameter, execute =>
+            {
+                void Handler(object? s, EventArgs e) => execute();
+                addHandler(Handler);
+                return new ActionDisposable(() => removeHandler(Handler));
+            });
+    }
 
+    /// <summary>
+    /// Shared command-binding core: subscribes the command parameter, attaches the event handler that executes the
+    /// command when it can, and — for <see cref="Component"/> targets that expose an <c>Enabled</c> property — keeps
+    /// that property in sync with <see cref="ICommand.CanExecute(object?)"/>. Each public overload supplies
+    /// <paramref name="subscribeHandler"/> to wire its own strongly typed event delegate; everything else is identical.
+    /// </summary>
+    /// <param name="command">The command to bind.</param>
+    /// <param name="target">The target object whose <c>Enabled</c> property is synchronized.</param>
+    /// <param name="targetType">The declared target type used to discover the <c>Enabled</c> property.</param>
+    /// <param name="commandParameter">An observable that supplies command parameter values.</param>
+    /// <param name="subscribeHandler">Attaches a handler that invokes the supplied callback when the event fires and returns a disposable that detaches it.</param>
+    /// <returns>A disposable that unbinds the command.</returns>
+    private static MultipleDisposable BindToHandler(
+        ICommand command,
+        object target,
+        Type targetType,
+        IObservable<object?> commandParameter,
+        Func<Action, IDisposable> subscribeHandler)
+    {
         object? latestParameter = null;
 
-        void Handler(object? s, EventArgs e)
+        var ret = new MultipleDisposable { commandParameter.Subscribe(new DelegateObserver<object?>(x => Volatile.Write(ref latestParameter, x))) };
+
+        ret.Add(subscribeHandler(() =>
         {
             var param = Volatile.Read(ref latestParameter);
             if (!command.CanExecute(param))
@@ -332,34 +319,28 @@ void Handler(object? s, EventArgs e)
             }
 
             command.Execute(param);
-        }
-
-        var ret = new MultipleDisposable { commandParameter.Subscribe(new DelegateObserver<object?>(x => Volatile.Write(ref latestParameter, x))) };
-
-        addHandler(Handler);
-        ret.Add(new ActionDisposable(() => removeHandler(Handler)));
+        }));
 
-        // Handle Enabled property binding for Components
-        var targetType = typeof(T);
+        // We initially only accepted Controls here, but this is too restrictive: there are a number of
+        // Components that can trigger Commands and also have an Enabled property, just like Controls
+        // (for example System.Windows.Forms.ToolStripButton).
         if (typeof(Component).IsAssignableFrom(targetType))
         {
             var enabledProperty = targetType.GetRuntimeProperty("Enabled");
 
-            if (enabledProperty is null)
+            if (enabledProperty is not null)
             {
-                return ret;
+                // Replaces FromEvent(CanExecuteChanged).StartWith(initial).Subscribe(...).
+                var canExecuteChanged = new FromEventObservable<bool>(onNext =>
+                {
+                    void CanExecuteHandler(object? sender, EventArgs e) => onNext(command.CanExecute(Volatile.Read(ref latestParameter)));
+                    command.CanExecuteChanged += CanExecuteHandler;
+                    return new ActionDisposable(() => command.CanExecuteChanged -= CanExecuteHandler);
+                });
+
+                ret.Add(new StartWithObservable<bool>(canExecuteChanged, command.CanExecute(Volatile.Read(ref latestParameter)))
+                    .Subscribe(new DelegateObserver<bool>(x => enabledProperty.SetValue(target, x, null))));
             }
-
-            // Replaces FromEvent(CanExecuteChanged).StartWith(initial).Subscribe(...).
-            var canExecuteChanged = new FromEventObservable<bool>(onNext =>
-            {
-                void CanExecuteHandler(object? sender, EventArgs e) => onNext(command.CanExecute(Volatile.Read(ref latestParameter)));
-                command.CanExecuteChanged += CanExecuteHandler;
-                return new ActionDisposable(() => command.CanExecuteChanged -= CanExecuteHandler);
-            });
-
-            ret.Add(new StartWithObservable<bool>(canExecuteChanged, command.CanExecute(latestParameter))
-                .Subscribe(new DelegateObserver<bool>(x => enabledProperty.SetValue(target, x, null))));
         }
 
         return ret;
diff --git a/src/ReactiveUI/Platforms/android/BundleSuspensionDriver.cs b/src/ReactiveUI/Platforms/android/BundleSuspensionDriver.cs
index 2331863ba6..fb1d31b32f 100644
--- a/src/ReactiveUI/Platforms/android/BundleSuspensionDriver.cs
+++ b/src/ReactiveUI/Platforms/android/BundleSuspensionDriver.cs
@@ -102,7 +102,7 @@ public IObservable<RxVoid> SaveState<T>(T state)
             JsonSerializer.Serialize(stream, state);
 
             AutoSuspendHelper.LatestBundle?.PutByteArray(StateKey, stream.ToArray());
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
         catch (Exception ex)
         {
@@ -121,7 +121,7 @@ public IObservable<RxVoid> SaveState<T>(T state, JsonTypeInfo<T> typeInfo)
             JsonSerializer.Serialize(stream, state, typeInfo);
 
             AutoSuspendHelper.LatestBundle?.PutByteArray(StateKey, stream.ToArray());
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
         catch (Exception ex)
         {
@@ -135,7 +135,7 @@ public IObservable<RxVoid> InvalidateState()
         try
         {
             AutoSuspendHelper.LatestBundle?.PutByteArray(StateKey, []);
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
         catch (Exception ex)
         {
diff --git a/src/ReactiveUI/Platforms/android/FlexibleCommandBinder.cs b/src/ReactiveUI/Platforms/android/FlexibleCommandBinder.cs
index 0261df42b5..9b3146e597 100644
--- a/src/ReactiveUI/Platforms/android/FlexibleCommandBinder.cs
+++ b/src/ReactiveUI/Platforms/android/FlexibleCommandBinder.cs
@@ -134,13 +134,6 @@ public IDisposable? BindCommandToObject<
             return EmptyDisposable.Instance;
         }
 
-        commandParameter ??= new SingleValueObservable<object?>(target);
-
-        object? latestParam = null;
-
-        var parameterSub = commandParameter.Subscribe(new DelegateObserver<object?>(x => Volatile.Write(ref latestParam, x)));
-        addHandler(Handler);
-
         Action<object?, object?, object?[]?>? enabledSetter = null;
         try
         {
@@ -155,34 +148,12 @@ public IDisposable? BindCommandToObject<
             enabledSetter = null;
         }
 
-        IDisposable? canExecuteSub = null;
-        if (enabledSetter is not null)
-        {
-            enabledSetter(target, command.CanExecute(Volatile.Read(ref latestParam)), null);
-
-            canExecuteSub = new CanExecuteChangedObservable(command, () => command.CanExecute(Volatile.Read(ref latestParam)))
-                .Subscribe(new DelegateObserver<bool>(x => enabledSetter(target, x, null)));
-        }
-
-        return canExecuteSub is null
-            ? new MultipleDisposable(
-                parameterSub,
-                new ActionDisposable(() => removeHandler(Handler)))
-            : new MultipleDisposable(
-                parameterSub,
-                canExecuteSub,
-                new ActionDisposable(() => removeHandler(Handler)));
-
-        void Handler(object? sender, TEventArgs e)
+        return BindEvent(command, target, commandParameter, enabledSetter, execute =>
         {
-            var param = Volatile.Read(ref latestParam);
-            if (!command.CanExecute(param))
-            {
-                return;
-            }
-
-            command.Execute(param);
-        }
+            void Handler(object? sender, TEventArgs e) => execute();
+            addHandler(Handler);
+            return new ActionDisposable(() => removeHandler(Handler));
+        });
     }
 
     /// <summary>Creates a commands binding from event and a property.</summary>
@@ -202,7 +173,7 @@ protected static IDisposable ForEvent(
     {
         ArgumentExceptionHelper.ThrowIfNull(command);
 
-        commandParameter ??= new SingleValueObservable<object?>(target);
+        commandParameter ??= new ReturnSignal<object?>(target, Sequencer.Immediate);
 
         object? latestParam = null;
         var ctl = target!;
@@ -264,41 +235,12 @@ protected static IDisposable ForEvent<TEventArgs>(
         ArgumentExceptionHelper.ThrowIfNull(addHandler);
         ArgumentExceptionHelper.ThrowIfNull(removeHandler);
 
-        commandParameter ??= new SingleValueObservable<object?>(target);
-
-        object? latestParam = null;
-
-        var parameterSub = commandParameter.Subscribe(new DelegateObserver<object?>(x => Volatile.Write(ref latestParam, x)));
-
-        addHandler(Handler);
-
-        if (enabledSetter is null)
-        {
-            return new MultipleDisposable(
-                parameterSub,
-                new ActionDisposable(() => removeHandler(Handler)));
-        }
-
-        enabledSetter(target, command.CanExecute(Volatile.Read(ref latestParam)), null);
-
-        var canExecuteSub = new CanExecuteChangedObservable(command, () => command.CanExecute(Volatile.Read(ref latestParam)))
-            .Subscribe(new DelegateObserver<bool>(x => enabledSetter(target, x, null)));
-
-        return new MultipleDisposable(
-            parameterSub,
-            canExecuteSub,
-            new ActionDisposable(() => removeHandler(Handler)));
-
-        void Handler(object? sender, TEventArgs e)
+        return BindEvent(command, target, commandParameter, enabledSetter, execute =>
         {
-            var param = Volatile.Read(ref latestParam);
-            if (!command.CanExecute(param))
-            {
-                return;
-            }
-
-            command.Execute(param);
-        }
+            void Handler(object? sender, TEventArgs e) => execute();
+            addHandler(Handler);
+            return new ActionDisposable(() => removeHandler(Handler));
+        });
     }
 
     /// <summary>
@@ -331,19 +273,63 @@ protected static IDisposable ForEvent(
         ArgumentExceptionHelper.ThrowIfNull(addHandler);
         ArgumentExceptionHelper.ThrowIfNull(removeHandler);
 
-        commandParameter ??= new SingleValueObservable<object?>(target);
+        return BindEvent(command, target, commandParameter, enabledSetter, execute =>
+        {
+            void Handler(object? sender, EventArgs e) => execute();
+            addHandler(Handler);
+            return new ActionDisposable(() => removeHandler(Handler));
+        });
+    }
+
+    /// <summary>Registers an observable factory for the specified type and property.</summary>
+    /// <param name="type">Type.</param>
+    /// <param name="affinity">The affinity for the type.</param>
+    /// <param name="createBinding">Creates the binding.</param>
+    protected void Register(
+        Type type,
+        int affinity,
+        Func<ICommand?, object?, IObservable<object?>, IDisposable> createBinding) =>
+        _config[type] = new() { Affinity = affinity, CreateBinding = createBinding };
+
+    /// <summary>
+    /// Shared command-binding core: subscribes the command parameter, attaches the event handler that executes the
+    /// command when it can, and optionally keeps an enabled-like property in sync with
+    /// <see cref="ICommand.CanExecute(object?)"/>. Each public overload supplies <paramref name="subscribeHandler"/>
+    /// to wire its own strongly typed event delegate; everything else is identical, so it lives here once.
+    /// </summary>
+    /// <param name="command">The command to bind.</param>
+    /// <param name="target">The event source object.</param>
+    /// <param name="commandParameter">Observable producing command parameter values. If <see langword="null"/>, <paramref name="target"/> is used.</param>
+    /// <param name="enabledSetter">Optional setter for an enabled-like property; enabled synchronization is skipped when <see langword="null"/>.</param>
+    /// <param name="subscribeHandler">Attaches a handler that invokes the supplied callback when the event fires and returns a disposable that detaches it.</param>
+    /// <returns>A disposable that unbinds the command and stops enabled synchronization.</returns>
+    private static MultipleDisposable BindEvent(
+        ICommand command,
+        object? target,
+        IObservable<object?>? commandParameter,
+        Action<object?, object?, object?[]?>? enabledSetter,
+        Func<Action, IDisposable> subscribeHandler)
+    {
+        commandParameter ??= new ReturnSignal<object?>(target, Sequencer.Immediate);
 
         object? latestParam = null;
 
         var parameterSub = commandParameter.Subscribe(new DelegateObserver<object?>(x => Volatile.Write(ref latestParam, x)));
 
-        addHandler(Handler);
+        var handlerSub = subscribeHandler(() =>
+        {
+            var param = Volatile.Read(ref latestParam);
+            if (!command.CanExecute(param))
+            {
+                return;
+            }
+
+            command.Execute(param);
+        });
 
         if (enabledSetter is null)
         {
-            return new MultipleDisposable(
-                parameterSub,
-                new ActionDisposable(() => removeHandler(Handler)));
+            return new MultipleDisposable(parameterSub, handlerSub);
         }
 
         enabledSetter(target, command.CanExecute(Volatile.Read(ref latestParam)), null);
@@ -351,33 +337,9 @@ protected static IDisposable ForEvent(
         var canExecuteSub = new CanExecuteChangedObservable(command, () => command.CanExecute(Volatile.Read(ref latestParam)))
             .Subscribe(new DelegateObserver<bool>(x => enabledSetter(target, x, null)));
 
-        return new MultipleDisposable(
-            parameterSub,
-            canExecuteSub,
-            new ActionDisposable(() => removeHandler(Handler)));
-
-        void Handler(object? sender, EventArgs e)
-        {
-            var param = Volatile.Read(ref latestParam);
-            if (!command.CanExecute(param))
-            {
-                return;
-            }
-
-            command.Execute(param);
-        }
+        return new MultipleDisposable(parameterSub, canExecuteSub, handlerSub);
     }
 
-    /// <summary>Registers an observable factory for the specified type and property.</summary>
-    /// <param name="type">Type.</param>
-    /// <param name="affinity">The affinity for the type.</param>
-    /// <param name="createBinding">Creates the binding.</param>
-    protected void Register(
-        Type type,
-        int affinity,
-        Func<ICommand?, object?, IObservable<object?>, IDisposable> createBinding) =>
-        _config[type] = new() { Affinity = affinity, CreateBinding = createBinding };
-
     /// <summary>
     /// Emits the command's current can-execute value each time <see cref="ICommand.CanExecuteChanged"/> fires —
     /// replacing <c>Observable.FromEvent</c> over that event. The handler is detached when the subscription is disposed.
diff --git a/src/ReactiveUI/Platforms/apple-common/AppSupportJsonSuspensionDriver.cs b/src/ReactiveUI/Platforms/apple-common/AppSupportJsonSuspensionDriver.cs
index 8f1ce6c4db..fcac376f36 100644
--- a/src/ReactiveUI/Platforms/apple-common/AppSupportJsonSuspensionDriver.cs
+++ b/src/ReactiveUI/Platforms/apple-common/AppSupportJsonSuspensionDriver.cs
@@ -118,7 +118,7 @@ public IObservable<RxVoid> SaveState<T>(T state, JsonTypeInfo<T> typeInfo)
             using var stream = File.Open(path, FileMode.Create, FileAccess.Write, FileShare.None);
 
             JsonSerializer.Serialize(stream, state, typeInfo);
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
         catch (Exception ex)
         {
@@ -137,7 +137,7 @@ public IObservable<RxVoid> SaveState<T>(T state)
             using var stream = File.Open(path, FileMode.Create, FileAccess.Write, FileShare.None);
 
             JsonSerializer.Serialize(stream, state);
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
         catch (Exception ex)
         {
@@ -153,7 +153,7 @@ public IObservable<RxVoid> InvalidateState()
             var path = GetStatePath();
             File.Delete(path);
 
-            return SingleValueObservable.Void;
+            return ImmutableReturnRxVoidSignal.Instance;
         }
         catch (Exception ex)
         {
diff --git a/src/tests/Directory.Build.props b/src/tests/Directory.Build.props
index d252ead629..4af54f4b33 100644
--- a/src/tests/Directory.Build.props
+++ b/src/tests/Directory.Build.props
@@ -27,6 +27,9 @@
        System.Reactive surface instead. All other lean test projects are System.Reactive-free and use the Primitives surface. -->
   <ItemGroup Condition="'$(RxReactiveSeam)' != 'true' and !$(MSBuildProjectName.Contains('Routing'))">
     <Using Include="ReactiveUI.Primitives" />
+    <!-- Concrete signal classes (ReturnSignal/StartSignal/ImmutableReturnRxVoidSignal) the tests construct
+         directly in place of the removed in-repo SingleValueObservable/SyncExecuteObservable sinks. -->
+    <Using Include="ReactiveUI.Primitives.Advanced" />
   </ItemGroup>
   <!-- BCL ObservableCollection replaces incidental DynamicData ObservableCollectionExtended in test mocks. -->
   <ItemGroup>
@@ -39,6 +42,7 @@
   </ItemGroup>
   <ItemGroup Condition="'$(RxReactiveSeam)' == 'true' and !$(MSBuildProjectName.Contains('Routing'))">
     <Using Include="ReactiveUI.Primitives.Reactive" />
+    <Using Include="ReactiveUI.Primitives.Reactive.Advanced" />
     <!-- The generic Signal<T> subject (and ReplaySignal/ScheduledSignal) is neutral — it ships in
          ReactiveUI.Primitives.Core under ReactiveUI.Primitives.Signals and is shared by both leaves; the engine
          seam (ReactiveShim.props) already imports that namespace. Only the NON-generic Signal static factory
diff --git a/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistCollectionTest.cs b/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistCollectionTest.cs
index e61af380b2..d86e125af5 100644
--- a/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistCollectionTest.cs
+++ b/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistCollectionTest.cs
@@ -47,7 +47,7 @@ public async Task AutoPersistCollection_Dispose_StopsAllPersistence()
             _ =>
             {
                 timesSaved++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
@@ -108,7 +108,7 @@ public async Task AutoPersistCollection_DuplicateAdd_NoDoubleSave()
             _ =>
             {
                 timesSaved++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
 
@@ -146,7 +146,7 @@ public async Task AutoPersistCollection_Lifecycle_ManagesPersistence()
             _ =>
             {
                 timesSaved++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
@@ -205,7 +205,7 @@ public async Task AutoPersistCollection_ManualSave_TriggersImmediateSave()
             _ =>
             {
                 timesSaved++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
@@ -238,7 +238,7 @@ public async Task AutoPersistCollection_MetadataProvider_WorksCorrectly()
             _ =>
             {
                 timesSaved++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             ReactiveUI.Primitives.Signals.Signal.Silent<RxVoid>(),
             metadataProvider,
@@ -271,7 +271,7 @@ public async Task AutoPersistCollection_Reset_ContinuesPersistence()
             _ =>
             {
                 timesSaved++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
 
diff --git a/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistHelperTest.cs b/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistHelperTest.cs
index d4fef92099..f170bc7fa6 100644
--- a/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistHelperTest.cs
+++ b/src/tests/ReactiveUI.Tests/AutoPersist/AutoPersistHelperTest.cs
@@ -259,7 +259,7 @@ public async Task AutoPersist_Dispose_StopsSaving()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(1));
 
@@ -294,7 +294,7 @@ public async Task AutoPersist_ManualSaveSignal_TriggersSave()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             TimeSpan.FromSeconds(1));
@@ -331,7 +331,7 @@ public async Task AutoPersist_NoDataContract_ThrowsArgumentException()
 
         await Assert.ThrowsAsync<ArgumentException>(async () =>
         {
-            _ = obj.AutoPersist(_ => SingleValueObservable.Void);
+            _ = obj.AutoPersist(_ => ImmutableReturnRxVoidSignal.Instance);
             await Task.CompletedTask;
         });
     }
@@ -351,7 +351,7 @@ public async Task AutoPersist_NonDataMemberProperty_DoesNotTriggerSave()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(1));
 
@@ -387,7 +387,7 @@ public async Task AutoPersist_NullManualSaveSignal_ThrowsArgumentNullException()
 
         await Assert.ThrowsAsync<ArgumentNullException>(async () =>
         {
-            _ = fixture.AutoPersist(_ => SingleValueObservable.Void, null!, TimeSpan.FromSeconds(1));
+            _ = fixture.AutoPersist(_ => ImmutableReturnRxVoidSignal.Instance, null!, TimeSpan.FromSeconds(1));
             await Task.CompletedTask;
         });
     }
@@ -405,7 +405,7 @@ public async Task AutoPersist_NullMetadata_ThrowsArgumentNullException()
 
         await Assert.ThrowsAsync<ArgumentNullException>(async () =>
         {
-            _ = fixture.AutoPersist(_ => SingleValueObservable.Void, null!, TimeSpan.FromSeconds(1));
+            _ = fixture.AutoPersist(_ => ImmutableReturnRxVoidSignal.Instance, null!, TimeSpan.FromSeconds(1));
             await Task.CompletedTask;
         });
     }
@@ -425,7 +425,7 @@ public async Task AutoPersist_PropertyChange_TriggersSave()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(1));
 
@@ -452,7 +452,7 @@ public async Task AutoPersist_Throttle_RespectInterval()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(ThrottleSeconds));
 
@@ -486,7 +486,7 @@ public async Task AutoPersist_WithMetadata_SavesCorrectly()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             metadata,
             TimeSpan.FromSeconds(1));
@@ -513,7 +513,7 @@ public async Task AutoPersistCollection_AddItem_EnablesPersistence()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
 
@@ -538,7 +538,7 @@ public async Task AutoPersistCollection_NullCollection_ThrowsArgumentNullExcepti
 
         await Assert.ThrowsAsync<ArgumentNullException>(async () =>
         {
-            _ = collection!.AutoPersistCollection(_ => SingleValueObservable.Void);
+            _ = collection!.AutoPersistCollection(_ => ImmutableReturnRxVoidSignal.Instance);
             await Task.CompletedTask;
         });
     }
@@ -566,7 +566,7 @@ public async Task AutoPersistCollection_NullMetadata_ThrowsArgumentNullException
 
         await Assert.ThrowsAsync<ArgumentNullException>(async () =>
         {
-            _ = collection.AutoPersistCollection(_ => SingleValueObservable.Void, (AutoPersistHelperMixins.AutoPersistMetadata)null!);
+            _ = collection.AutoPersistCollection(_ => ImmutableReturnRxVoidSignal.Instance, (AutoPersistHelperMixins.AutoPersistMetadata)null!);
             await Task.CompletedTask;
         });
     }
@@ -588,7 +588,7 @@ public async Task AutoPersistCollection_ReadOnlyCollection_WorksCorrectly()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
@@ -621,7 +621,7 @@ public async Task AutoPersistCollection_RemoveItem_DisablesPersistence()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
 
@@ -651,7 +651,7 @@ public async Task AutoPersistCollection_WithMetadata_SavesCorrectly()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             metadata,
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
@@ -731,7 +731,7 @@ public async Task AutoPersistCollection_ManualSignalAndMetadataNoInterval_SavesC
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             metadata);
@@ -764,7 +764,7 @@ public async Task AutoPersistCollection_ManualSignalNoInterval_SavesCorrectly()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave);
 
@@ -798,7 +798,7 @@ public async Task AutoPersistCollection_ReadOnlyManualSignalAndMetadataNoInterva
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             metadata);
@@ -832,7 +832,7 @@ public async Task AutoPersistCollection_ReadOnlyManualSignalNoInterval_SavesCorr
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave);
 
@@ -865,7 +865,7 @@ public async Task AutoPersistCollection_MetadataProviderNoInterval_SavesCorrectl
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             metadataProvider);
@@ -901,7 +901,7 @@ public async Task AutoPersistCollection_MetadataProviderDispose_StopsPersistence
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             new Signal<RxVoid>(),
             metadataProvider,
@@ -934,7 +934,7 @@ public async Task AutoPersistCollection_MetadataWithoutDataContract_ThrowsArgume
 
         await Assert.ThrowsAsync<ArgumentException>(async () =>
         {
-            _ = collection.AutoPersistCollection(_ => SingleValueObservable.Void, new Signal<RxVoid>(), metadata, interval: null);
+            _ = collection.AutoPersistCollection(_ => ImmutableReturnRxVoidSignal.Instance, new Signal<RxVoid>(), metadata, interval: null);
             await Task.CompletedTask;
         });
     }
@@ -957,7 +957,7 @@ public async Task AutoPersistCollection_GenericMetadataNoInterval_SavesCorrectly
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave,
             metadata);
@@ -990,7 +990,7 @@ public async Task AutoPersist_DisposeWithPendingSave_DoesNotPersist()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(IntervalSeconds));
 
@@ -1020,7 +1020,7 @@ public async Task AutoPersist_NonPersistableRaisedProperty_DoesNotTriggerSave()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(1));
 
@@ -1048,7 +1048,7 @@ public async Task AutoPersist_ManualSignalNoInterval_SavesCorrectly()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave);
 
@@ -1079,7 +1079,7 @@ public async Task AutoPersist_DerivedRuntimeType_UsesRuntimeMetadata()
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             TimeSpan.FromSeconds(1));
 
@@ -1156,7 +1156,7 @@ public async Task AutoPersistCollection_ReplaceUntrackedPrevious_DisposeAndRemov
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             new Signal<RxVoid>(),
             TimeSpan.FromMilliseconds(ThrottleMilliseconds));
@@ -1191,7 +1191,7 @@ public async Task AutoPersistCollection_GenericReflectionManualSignalNoInterval_
             _ =>
             {
                 saveCount++;
-                return SingleValueObservable.Void;
+                return ImmutableReturnRxVoidSignal.Instance;
             },
             manualSave);
 
diff --git a/src/tests/ReactiveUI.Tests/Commands/CombinedReactiveCommandTest.cs b/src/tests/ReactiveUI.Tests/Commands/CombinedReactiveCommandTest.cs
index 4f069dde79..9d1de4ff89 100644
--- a/src/tests/ReactiveUI.Tests/Commands/CombinedReactiveCommandTest.cs
+++ b/src/tests/ReactiveUI.Tests/Commands/CombinedReactiveCommandTest.cs
@@ -29,11 +29,11 @@ public class CombinedReactiveCommandTest
     public async Task CanExecuteIsFalseIfAnyChildCannotExecute()
     {
         var child1 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child2 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
-            SingleValueObservable.False,
+            static () => ImmutableReturnRxVoidSignal.Instance,
+            new ReturnSignal<bool>(false, Sequencer.Immediate),
             Sequencer.Immediate);
         var childCommands = new[] { child1, child2 };
         var fixture = ReactiveCommand.CreateCombined(childCommands, outputScheduler: Sequencer.Immediate);
@@ -49,13 +49,13 @@ public async Task CanExecuteIsFalseIfAnyChildCannotExecute()
     public async Task CanExecuteIsFalseIfParentCanExecuteIsFalse()
     {
         var child1 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child2 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var childCommands = new[] { child1, child2 };
-        var fixture = ReactiveCommand.CreateCombined(childCommands, SingleValueObservable.False, Sequencer.Immediate);
+        var fixture = ReactiveCommand.CreateCombined(childCommands, new ReturnSignal<bool>(false, Sequencer.Immediate), Sequencer.Immediate);
         var canExecute = fixture.CanExecute.Collect();
 
         await Assert.That(canExecute).Count().IsEqualTo(1);
@@ -69,10 +69,10 @@ public async Task CanExecuteTicksFailuresInChildCanExecuteThroughThrownException
     {
         var canExecuteSubject = new Signal<bool>();
         var child1 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child2 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             canExecuteSubject,
             Sequencer.Immediate);
         var childCommands = new[] { child1, child2 };
@@ -92,10 +92,10 @@ public async Task CanExecuteTicksFailuresThroughThrownExceptions()
     {
         var canExecuteSubject = new Signal<bool>();
         var child1 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child2 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var childCommands = new[] { child1, child2 };
         var fixture = ReactiveCommand.CreateCombined(childCommands, canExecuteSubject, Sequencer.Immediate);
@@ -132,13 +132,13 @@ public async Task ExceptionsAreDeliveredOnOutputScheduler()
     public async Task ExecuteExecutesAllChildCommands()
     {
         var child1 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child2 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child3 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var childCommands = new[] { child1, child2, child3 };
         var fixture = ReactiveCommand.CreateCombined(childCommands, outputScheduler: Sequencer.Immediate);
@@ -192,7 +192,7 @@ public async Task ExecuteExecutesAllChildCommands()
     public async Task ExecuteTicksErrorsInAnyChildCommandThroughThrownExceptions()
     {
         var child1 = ReactiveCommand.CreateFromObservable(
-            static () => SingleValueObservable.Void,
+            static () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: Sequencer.Immediate);
         var child2 = ReactiveCommand.CreateFromObservable(
             static () => Signal.Fail<RxVoid>(new InvalidOperationException("oops")),
diff --git a/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.ExecutionAndInvoke.cs b/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.ExecutionAndInvoke.cs
index 87601591df..64fffeef93 100644
--- a/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.ExecutionAndInvoke.cs
+++ b/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.ExecutionAndInvoke.cs
@@ -25,7 +25,7 @@ public partial class ReactiveCommandTest
     public async Task Execute_CanBeCancelled()
     {
         var scheduler = TestContext.Current.GetVirtualTimeScheduler();
-        var execute = SingleValueObservable.Void.Delay(TimeSpan.FromSeconds(1), scheduler);
+        var execute = ImmutableReturnRxVoidSignal.Instance.Delay(TimeSpan.FromSeconds(1), scheduler);
         var command = ReactiveCommand.CreateFromObservable<RxVoid>(
             () => execute,
             outputScheduler: scheduler);
@@ -175,7 +175,7 @@ public async Task Execute_TicksMultipleResults()
     public async Task ICommand_CanExecute_IsFalseWhileExecuting()
     {
         var scheduler = TestContext.Current.GetVirtualTimeScheduler();
-        var execute = SingleValueObservable.Void.Delay(TimeSpan.FromSeconds(1), scheduler);
+        var execute = ImmutableReturnRxVoidSignal.Instance.Delay(TimeSpan.FromSeconds(1), scheduler);
         ICommand command = ReactiveCommand.CreateFromObservable<RxVoid>(
             () => execute,
             outputScheduler: scheduler);
diff --git a/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.IsExecutingAndExceptions.cs b/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.IsExecutingAndExceptions.cs
index fdcc68ab34..79ac81459d 100644
--- a/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.IsExecutingAndExceptions.cs
+++ b/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.IsExecutingAndExceptions.cs
@@ -25,7 +25,7 @@ public async Task IsExecuting_HandlesMultipleInFlightExecutions()
         const int DelayMilliseconds = 500;
 
         var scheduler = TestContext.Current.GetVirtualTimeScheduler();
-        var execute = SingleValueObservable.Void.Delay(TimeSpan.FromMilliseconds(DelayMilliseconds), scheduler);
+        var execute = ImmutableReturnRxVoidSignal.Instance.Delay(TimeSpan.FromMilliseconds(DelayMilliseconds), scheduler);
         var command = ReactiveCommand.CreateFromObservable<RxVoid>(
             () => execute,
             outputScheduler: scheduler);
@@ -84,7 +84,7 @@ public async Task IsExecuting_RemainsTrue_UntilExecutionCompletes()
     public async Task IsExecuting_TicksWhileExecuting()
     {
         var scheduler = TestContext.Current.GetVirtualTimeScheduler();
-        var execute = SingleValueObservable.Void.Delay(TimeSpan.FromSeconds(1), scheduler);
+        var execute = ImmutableReturnRxVoidSignal.Instance.Delay(TimeSpan.FromSeconds(1), scheduler);
         var command = ReactiveCommand.CreateFromObservable<RxVoid>(
             () => execute,
             outputScheduler: scheduler);
@@ -180,7 +180,7 @@ public async Task Scheduler_ResultsDeliveredOnOutputScheduler()
     {
         var scheduler = TestContext.Current!.GetScheduler();
         var command = ReactiveCommand.CreateFromObservable(
-            () => SingleValueObservable.Void,
+            () => ImmutableReturnRxVoidSignal.Instance,
             outputScheduler: scheduler);
         var executed = false;
 
diff --git a/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.cs b/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.cs
index 49095fa6e0..8bfb447ed7 100644
--- a/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.cs
+++ b/src/tests/ReactiveUI.Tests/Commands/ReactiveCommandTest.cs
@@ -65,7 +65,7 @@ public async Task CanExecute_IsBehavioral()
     public async Task CanExecute_IsFalseWhileExecuting()
     {
         var scheduler = TestContext.Current.GetVirtualTimeScheduler();
-        var execute = SingleValueObservable.Void.Delay(TimeSpan.FromSeconds(1), scheduler);
+        var execute = ImmutableReturnRxVoidSignal.Instance.Delay(TimeSpan.FromSeconds(1), scheduler);
         var command = ReactiveCommand.CreateFromObservable<RxVoid>(
             () => execute,
             outputScheduler: scheduler);
diff --git a/src/tests/ReactiveUI.Tests/Core/ObservablesTests.cs b/src/tests/ReactiveUI.Tests/Core/ObservablesTests.cs
deleted file mode 100644
index a809908ff6..0000000000
--- a/src/tests/ReactiveUI.Tests/Core/ObservablesTests.cs
+++ /dev/null
@@ -1,73 +0,0 @@
-// Copyright (c) 2009-2026 .NET Foundation and Contributors. All rights reserved.
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for full license information.
-
-#if !REACTIVE_SHIM
-using ReactiveUI.Internal;
-#endif
-
-namespace ReactiveUI.Tests.Core;
-
-/// <summary>Tests for Observables static utility class.</summary>
-public class ObservablesTests
-{
-    /// <summary>Tests that SingleValueObservable.False emits false value.</summary>
-    /// <returns>A <see cref="Task" /> representing the asynchronous operation.</returns>
-    [Test]
-    public async Task Observables_False_EmitsFalse()
-    {
-        // Arrange
-        bool? result = null;
-
-        // Act
-        _ = SingleValueObservable.False.Subscribe(x => result = x);
-
-        // Assert
-        await Assert.That(result).IsFalse();
-    }
-
-    /// <summary>Tests that Observables static members are accessible.</summary>
-    /// <returns>A <see cref="Task" /> representing the asynchronous operation.</returns>
-    [Test]
-    public async Task Observables_StaticMembers_AreAccessible()
-    {
-        using (Assert.Multiple())
-        {
-            // Act & Assert
-            await Assert.That(SingleValueObservable.Void).IsNotNull();
-            await Assert.That(SingleValueObservable.True).IsNotNull();
-            await Assert.That(SingleValueObservable.False).IsNotNull();
-        }
-    }
-
-    /// <summary>Tests that SingleValueObservable.True emits true value.</summary>
-    /// <returns>A <see cref="Task" /> representing the asynchronous operation.</returns>
-    [Test]
-    public async Task Observables_True_EmitsTrue()
-    {
-        // Arrange
-        bool? result = null;
-
-        // Act
-        _ = SingleValueObservable.True.Subscribe(x => result = x);
-
-        // Assert
-        await Assert.That(result).IsTrue();
-    }
-
-    /// <summary>Tests that SingleValueObservable.Void emits RxVoid.Default value.</summary>
-    /// <returns>A <see cref="Task" /> representing the asynchronous operation.</returns>
-    [Test]
-    public async Task Observables_Unit_EmitsUnitDefault()
-    {
-        // Arrange
-        RxVoid? result = null;
-
-        // Act
-        _ = SingleValueObservable.Void.Subscribe(x => result = x);
-
-        // Assert
-        await Assert.That(result).IsEqualTo(RxVoid.Default);
-    }
-}
diff --git a/src/tests/ReactiveUI.Tests/InteractionsTest.cs b/src/tests/ReactiveUI.Tests/InteractionsTest.cs
index dbefe4df23..81036ed95b 100644
--- a/src/tests/ReactiveUI.Tests/InteractionsTest.cs
+++ b/src/tests/ReactiveUI.Tests/InteractionsTest.cs
@@ -103,7 +103,7 @@ public async Task HandlersCanContainAsynchronousCode()
             handler1AWasCalled = true;
         });
         var handler1B = interaction.RegisterHandler(x =>
-            SingleValueObservable.Void.Delay(TimeSpan.FromSeconds(1), scheduler)
+            ImmutableReturnRxVoidSignal.Instance.Delay(TimeSpan.FromSeconds(1), scheduler)
                 .Do(_ => x.SetOutput(OutputB)));
 
         using (handler1A)