Clearly identify request start and end events. Current request end event
is detected in one of two ways:
	- Client starts to write a new request while request state was
	  REQ_READ_RESPONSE. This happens when multiple requests are
	sent using the same connection using keep alive.
	- Communication channel is shutdown due to disconnect by either
	  client or server. This is a bit tricky because connection may
	be kept open for a long time. We need to better detect end of response
	using Content-Length response header.

Beef up logging for better debugging.
Remove file.