private void ExecuteCallback()
            {
                if (_executed)
                {
                    return;
                }

                _executed = true;
                Roots.UntangleAnonymously(this);
                _callAfterSleep();
            }
 private void ExecuteCallback()
 {
     Roots.UntangleAnonymously(this);
     _awaitable.SignalCompletion();
 }