how to read $body_bytes_sent nginx variable

[Phani Sreenivasa Prasad]

on my dev setup, the logs are disabled due to memory constraint. Also the
log_format directive would log many more fields into that file which I am 
not interested in.

is there a way I can read it through fastcgi param from my fastcgi app? I
see one problem here is - nginx sends all env variables as a record when the
request comes initially and later on it doesnt send any more env variables
after sending the response. 

Any solution for this?

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,271108,271115#msg-271115