nginx has problem sending request body to upstream

[allenhe]

I understand the connection establish timer, write timer and read timer
should be setup and removed in order, but where is the write timer? are
there lines in the logs saying I'm going to send the bytes, the sending is
on-going, and the bytes has been sent out?

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,283735,283758#msg-283758