I was recently considering a similar patch for mod_proxy along the lines of spool_reqbody_cl() method but it would go one step further: spawning off a thread to asynchronously read the request into a temp file (or files) while the initial thread would continue to stream the io_bufsize chunks down the filter chain. This would 'untie' the original client and the proxy server in cases where they ran at different speeds (more a problem for *large* proxy files where one side or the other could be tied up waiting for the slower side for long periods of time... and poor Apache caught in the middle).
One thought I have been tossing around for a long time is tying the proxy code into the Event MPM. Instead of a thread blocking while it waits for a backend reply, the backend server's FD would be added to the Event Thread, and then when the reply is ready, any available worker thread would handle it, like they do new requests.
This would work well for backend servers that might take a second or two for a reply, but it does add at least 3 context switches. (in some use cases this would work great, in others, it would hurt performance...)
-Paul
