Async with ManualResetEventSlim

AsyncManualResetEvent.cs

// https://blogs.msdn.microsoft.com/calvin_hsia/2018/09/29/using-async-with-manualreseteventslim/
// https://blogs.msdn.microsoft.com/pfxteam/2012/02/11/building-async-coordination-primitives-part-1-asyncmanualresetevent/
    internal class AsyncManualResetEvent
    {
        private volatile TaskCompletionSource<bool> tcs = new TaskCompletionSource<bool>();
 
        public Task WaitAsync() => this.tcs.Task;
 
        public void Set()
        {
            // https://stackoverflow.com/questions/12693046/configuring-the-continuation-behaviour-of-a-taskcompletionsources-task
            Task.Run(() =>
            this.tcs.TrySetResult(true));
        }
 
        public void Reset()
        {
            while (true)
            {
                var tcs = this.tcs;
                if (!tcs.Task.IsCompleted ||
                    Interlocked.CompareExchange(ref this.tcs, new TaskCompletionSource<bool>(), tcs) == tcs)
                {
                    return;
                }
            }
        }
    }