I've had some trouble with ASIHTTPRequest. It times out sending POST requests (with decent sized payloads) sending to our Rails server, upwards of 98% of the time. (I've literally only gotten one request to return properly.) Because I'm a masochist, I wrote a minimal replacement using the CFSocket API, and it works fine, every time.
My fear/guess is that something that ASIHTTPRequest is using is assuming that it can bombard the socket with data even when the output buffer gets full. At least that's the initial problem I had when I was writing my replacement, and after staring at ASIHTTPRequest for days, I can't think of anything else.
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