Gets a System.Threading.WaitHandle that is used to wait for an asynchronous operation to complete.
a System.Threading.WaitHandle
The System.Threading.WaitHandle can be used to perform a System.Threading.WaitHandle.WaitOne(int, bool), System.Threading.WaitHandle.WaitAny(System.Threading.WaitHandle[], int, bool), or System.Threading.WaitHandle.WaitAll(System.Threading.WaitHandle[], int, bool) to wait for the asynchronous call to complete.
For more details, see IAsyncResult.AsyncWaitHandle.