Fix TryObtainLockAsync(TimeSpan.Zero) overload

In the case of a zero timeout, the underlying async lock would be left in an
inconsistent state causing a subsequent attempt to obtain the lock to deadlock.

Author: mqudsi

AsyncLock/AsyncLock.cs

@@ -88,6 +88,11 @@ internal async Task<IDisposable> ObtainLockAsync(CancellationToken ct = default)
                 {
                     if (await TryEnterAsync(timeout))
                     {
+                        // Reset the owning thread id after all await calls have finished, otherwise we
+                        // could be resumed on a different thread and set an incorrect value.
+                        _parent._owningThreadId = ThreadId;
+                        // In case of !synchronous and success, TryEnter() does not release the reentrancy lock
+                        _parent._reentrancy.Release();
                         return this;
                     }
                     return null;