My understanding is that abrupt client disconnects are transparent through nginx -- the connection to upstream is closed and the upstream should handle that as it can. Please correct me if I am wrong.
Is there a way to use a call-back (or something similar, a redirect), in nginx.conf, for client disconnects? This would be useful when the upstream is not good at directly handling the disconnect (not async, and still processing the response for the now-disconnected client). This could help clean up resources, on a parallel channel.

Best,
George