Added missing Wait documentation

Author: slu-it

documentation/chapters/waiting.md

@@ -1,10 +1,16 @@
 [Home](../README.md)
 
 # The Waits Utility Class
-The `Wait` utility class provides a fluent API for all kinds of wait operations. This includes waiting an exact amount of 
-time and waiting for certain conditions with a timeout.
+The `Wait` utility class provides a fluent API for all kinds of wait operations.
+This includes waiting an exact amount of time and waiting for certain conditions
+with a timeout.
 
-## Examples
+**There are 3 distinct kinds of Wait operations:**
+1. Waiting an exact amount of time: `Wait.exactly(..)`
+2. Waiting until an object state is reached: `Wait.until(..)`
+3. Waiting until an object supplier return value's state is reached: `Wait.untilSupplied(..)`
+
+**Examples**
 ```java
 // waits 5 seconds
 Wait.exactly(5, TimeUnit.SECONDS);
@@ -16,12 +22,50 @@ Wait.exactly(150, TimeUnit.MILLISECONDS);
 Wait.exactly(1, TimeUnit.HOURS);
 
 // waits until the hidden field is visible on the DOM - with default timeout
+PageFragment hiddenField = ...;
 Wait.until(hiddenField).is(visible());
 
 // waits until the hidden field is visible on the DOM - with custom timeout
 Wait.withTimeoutOf(10, TimeUnit.SECONDS).until(hiddenField).is(visible());
+
+// waits until the call to 'findMany(".foo")' returns a non empty list
+Wait.untilSupplied(() -> findMany(".foo")).is((foos) -> !foos.isEmpty());
 ```
 
+## Wait.exactly(...)
+
+This is the most primitive wait operation.
+It allows to wait for a specific amount of time.
+That amount is specified by to parameters: the amount and the time unit.
+
+The maximum precision for the wait operation is *milliseconds*.
+If any more precise unit is defined (e.g. nanoseconds), there will be no wait.
+
+## Wait.until(..)
+
+This kind of wait operation will take any object instance and allows for the
+definition of several conditions to be waited on in order.
+It is important to note that the conditions will always be evaluated against the
+initially specified instance!
+
+In the above example you can see a command which will wait until a 'hidden' field
+is visible. This will work because the given object is a `PageFragment`. Since
+page fragments act as proxies for `WebElement` instances, which are not cached,
+the check on visibility can return a different result for each invocation.
+
+But let's say, as an example, the given object is a list of page fragments and
+you want to wait until the list has a certain size. In this case the size of the
+list will never change unless it's contents is manipulated asynchronously.
+
+In order to check something like this take a look at `Wait.untilSupplied(..)`.
+
+## Wait.untilSupplied(..)
+
+This kind of wait operation will take an object supplier as its parameter.
+The supplier is invoked every time a condition is checked.
+With this approach you can wait until a dynamic object - like a list of
+page fragments - has a certain state (e.g. size).
+
 # Linked Documentation
 
 - [Conditions](conditions.md)