Replace private properties with readonly fields.

Author: RichardD2

src/EntityFrameworkCore.DataEncryption/Internal/ConverterBuilder`1.cs

@@ -22,9 +22,10 @@ internal ConverterBuilder(IEncryptionProvider encryptionProvider, Func<TModelTyp
             Encoder = encoder;
         }
 
-        private IEncryptionProvider EncryptionProvider { get; }
-        private Func<TModelType, byte[]> Decoder { get; }
-        private Func<Stream, TModelType> Encoder { get; }
+        private readonly IEncryptionProvider EncryptionProvider;
+        private readonly Func<TModelType, byte[]> Decoder;
+        private readonly Func<Stream, TModelType> Encoder;
+
         internal bool IsEmpty => Decoder is null || Encoder is null;
 
         internal void Deconstruct(out IEncryptionProvider encryptionProvider, out Func<TModelType, byte[]> decoder, out Func<Stream, TModelType> encoder)

src/EntityFrameworkCore.DataEncryption/Internal/ConverterBuilder`2.cs

@@ -27,9 +27,9 @@ internal ConverterBuilder(ConverterBuilder<TModelType> modelType, Func<TStoreTyp
             Encoder = encoder;
         }
 
-        private ConverterBuilder<TModelType> ModelType { get; }
-        private Func<TStoreType, byte[]> Decoder { get; }
-        private Func<Stream, TStoreType> Encoder { get; }
+        private readonly ConverterBuilder<TModelType> ModelType;
+        private readonly Func<TStoreType, byte[]> Decoder;
+        private readonly Func<Stream, TStoreType> Encoder;
 
         /// <summary>
         /// Builds the value converter.