multiple connections to a fastcgi server

Hello,

I want to build a fast cgi server application which can handles long
polling calls. There should be only one process of this fast cgi app
which handles all incoming requests.
I wrote an app which is similar to the threaded.c example in the fast
cgi sdk. (http://www.fastcgi.com/devkit/examples/threaded.c)
Before responding, my app will wait a certain time after an incoming
request. (For testing I only put a sleep() call above
FCGX_FPrintF(...) in threaded.c).
I tested with Lighttpd und nginx and got the same result: The second
call is blocked until the first one is finished. I think the method
FCGX_Accept_r(&request); blocks until FCGX_Finish_r(&request); is
called.
Does anyone has a running multithread fastcgi app?

Thanks
Marc