httpd and cgi

[Will]

I was wondering how httpd handles POST requests to cgi.  Does it stream the 
body directly from the client to the cgi program?  If this is the case, what 
would be the downsides to streaming that to a file first and going from the 
file (most likely filesystem cache) to the stdin of the cgi program?  I 
think the obvious pro would be the cgi program would be open for a much 
shorter time.

-Will