CancellationTokenTaskSource`1 Holds the task for a cancellation token, as well as the token registration. The registration is disposed when this instance is disposed.

 SynchronizationContextSwitcher Utility class for temporarily switching implementations.

 AwaitableDisposable`1 An awaitable wrapper around a task whose result is disposable. The wrapper is not disposable, so this prevents usage errors like "using (MyAsync())" when the appropriate usage should be "using (await MyAsync())".

 SemaphoreSlimExtensions Provides extension methods for .

 SynchronizationContextExtensions Provides extension methods for .

 TaskCompletionSourceExtensions Provides extension methods for .

 TaskConstants Provides completed task constants.

 TaskConstants`1 Provides completed task constants.

 TaskExtensions Provides extension methods for the and types.

 TaskFactoryExtensions Provides extension methods for task factories.

 TaskHelper Helper methods for working with tasks.