IHttpAsyncHandler: Is the WaitHandle on the IAsyncResult returnedfrom BeginProcessRequest ever used by the HTTP application?

[UL-Tomten]

Is the WaitHandle on the IAsyncResult returned from
BeginProcessRequest ever used by the HTTP application? The reason I'm
asking is that in the MSDN article "How to: Create an Asynchronous
HTTP Handler"[1], BeginProcessRequest() returns an IAsyncResult whose
AsyncWaitHandle getter always returns null. Why is this? Is there some
guarantee that the HTTP application will never wait on a WaitHandle in
this situation? What does or doesn't the application do with the
returned IAsyncResult?

(After minimal testing using the code in the article, it doesn't seem
like the AsyncWaitHandle() getter is actually accessed during normal
operation.)

1: http://msdn2.microsoft.com/en-us/library/ms227433.aspx