Update awaiters to implement ICriticalNotifyCompletion

[sharwell]

This interface allows callers that preserve their own execution contexts to avoid a call to ExecutionContext.Capture and ExecutionContext.Run during an await operation.

• NoThrowTaskAwaiter
• ConfiguredTaskYieldAwaiter
• TaskSchedulerAwaiter
• JoinableTaskFactory+MainThreadAwaiter
• AsyncReaderWriterLock+Awaiter
• AsyncReaderWriterResourceLock+ResourceAwaiter
• InlineResumable

[AArnott]

I'm working on this now.

[AArnott]

For the NoThrowTaskAwaiter, offering ICriticalNotifyCompletion effected this change to a continuation's callstack. Note the drop from two ExecutionContext.Run frames to just one.

-OnCompleted
+UnsafeOnCompleted
 >      Microsoft.VisualStudio.Threading.Tests.dll!Microsoft.VisualStudio.Threading.Tests.TplExtensionsTests.NoThrowAwaitable_Await_CapturesExecutionContext.AnonymousMethod__0() Line 290      C#
        [Resuming Async Method]
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)  Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()        Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()     Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()        Unknown
        mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()       Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()        Unknown
-       mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.InvokeAction(object state)    Unknown
-       mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
-       mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
-       mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunCallback(System.Threading.ContextCallback callback, object state, ref System.Threading.Tasks.Task currentTask)     Unknown
-       mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.Run(System.Threading.Tasks.Task task, bool canInlineContinuationTask) Unknown
+       mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishStageThree()     Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Threading.Tasks.TaskCompletionSource<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Threading.Tasks.TaskCompletionSource<System.__Canon>.SetResult(System.__Canon result)       Unknown
        Microsoft.VisualStudio.Threading.Tests.dll!Microsoft.VisualStudio.Threading.Tests.TplExtensionsTests.NoThrowAwaitable_Await_CapturesExecutionContext(bool captureContext) Line 294      C#
        [Resuming Async Method]
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(object stateMachine)  Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()        Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.OutputAsyncCausalityEvents.AnonymousMethod__0()     Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()        Unknown
        mscorlib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__0()       Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()        Unknown
        mscorlib.dll!System.Threading.Tasks.SynchronizationContextAwaitTaskContinuation.GetActionLogDelegate.AnonymousMethod__0()       Unknown
        mscorlib.dll!System.Threading.Tasks.SynchronizationContextAwaitTaskContinuation..cctor.AnonymousMethod__8_0(object state)       Unknown
        xunit.execution.desktop.dll!Xunit.Sdk.AsyncTestSyncContext.Post.AnonymousMethod__0()    Unknown
        xunit.execution.desktop.dll!Xunit.Sdk.XunitWorkerThread.QueueUserWorkItem.AnonymousMethod__4_0(object _)        Unknown
        mscorlib.dll!System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(object state)      Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()  Unknown
        mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch()    Unknown
        mscorlib.dll!System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()     Unknown

[AArnott]

This issue can be closed when the two PRs linked above are merged.