[DotNetDevelopment] Is there any way to quickly determine a URL exist or not, instead of waiting for time out?

[Lianghua]

I know that we can use HttpWebRequest to try to get the response, but
most of time, when the URL is not available, I need wait for a timeout
or 404 error.  Is there any other way to complete this?  Specially I
need a quick way to do so, instead of waiting for time out?

thanks.

Leon