Multi threaded for HTTP web requests?

 Hello everyone,
I'm trying to understand more about the Http web requests to the Generic Handler ("IHttpHandler" class), can anyone kindly provide me some information? thanks in advance. 
I have the "IHttpHandler" class that handle the Http web requests, when the Http web requests hit the Generic Handler, will it creates a new thread for that request and abort the thread after the request has been completed?  will it creates a multiple threading for synchronous HTTP web requests?  Does anyone knows?
p.s I used the 'HttpWebRequest' and 'HttpWebResponse' for sending the request the Generic Handler and abort the HttpWebRequest after I got the response from the handler.
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