It looks like for Apache 2.2.10 on Windows, mod_proxy sends reverse proxy requests twice. I've verified this using two different packet sniffers. I also tracked the problem to the 'WSAsend' winsock call. If you alter the APR to use the 'send' winsock API call instead of the WSAsend call, then the problem goes away. I wonder if this is a winsock bug.
Ryan
