Awaitable AutoResetEvent

Question

What would be the async (awaitable) equivalent of AutoResetEvent?

If in the classic thread synchronization we would use something like this:

    AutoResetEvent signal = new AutoResetEvent(false);      void Thread1Proc()     {         //do some stuff         //..         //..          signal.WaitOne(); //wait for an outer thread to signal we are good to continue          //do some more stuff         //..         //..     }      void Thread2Proc()     {         //do some stuff         //..         //..          signal.Set(); //signal the other thread it's good to go          //do some more stuff         //..         //..     } 

I was hoping that in the new async way of doing things, something like this would come to be:

SomeAsyncAutoResetEvent asyncSignal = new SomeAsyncAutoResetEvent();  async void Task1Proc() {     //do some stuff     //..     //..      await asyncSignal.WaitOne(); //wait for an outer thread to signal we are good to continue      //do some more stuff     //..     //.. }  async void Task2Proc() {     //do some stuff     //..     //..      asyncSignal.Set(); //signal the other thread it's good to go      //do some more stuff     //..     //.. } 

I've seen other custom made solutions, but what I've managed to get my hands on, at some point in time, still involves locking a thread. I don't want this just for the sake of using the new await syntax. I'm looking for a true awaitable signaling mechanism which does not lock any thread.

Is it something I'm missing in the Task Parallel Library?

EDIT: Just to make clear: SomeAsyncAutoResetEvent is an entirely made up class name used as a placeholder in my example.

Answer 1

If you want to build your own, Stephen Toub has the definitive blog post on the subject.

If you want to use one that's already written, I have one in my AsyncEx library. AFAIK, there's no other option as of the time of this writing.