How to test if request has been aborted

[Tony Abo]

I am working on a custom request handler that works with Apache 2.x. There are 
times that the request may take a considerable amount of time to process. I 
need to cut the processing short if the user decides to press the stop button 
on the browser. I cant seem to figure out how to test for that condition from 
inside the handler. Can anyone help me?
 
Thanks in advance,
Tony