Senthil, I didn't clearly express my concern about send_response_only.  It doesn't look to me like, with buffering in place, that it *should* write directly, it looks to me like it should write to the buffer.  Consider specifically the fact that send_response_only is called from send_response_only, which is in turn called from send_error.

So IMO the unit test should at a minimum test that send_response_only buffers, and ideally it should test that send_error buffers (but that would require a somewhat different test harness since it would need to report that its write method was called only once).

I think the code you committed is still valid, it just doesn't quite do full header buffering.

And I agree that this should not be backported.