Collect request time, response time, user agent, remote addr and query params

[fntlnz]

• Request time (via Request time in the payload #5)
• Response time
• User agent
• Remote addr
• Query params
  For remote addr, the headers to consider are

X-Real-IP
X-Forwarded-For
X-Forwarded-Proto

For request time, req has a field:

req->start_msec

For upstream response time, req has a field:

req->upstream->state->response_tim

And for user agent there's the header

user_agent

[gianarb]

X-Forwarded-For
X-Forwarded-Proto

Perfect! I am not sure about Real-IP but I am fine

[fntlnz]

We might also want to check for pipelined requests: https://en.wikipedia.org/wiki/HTTP_pipelining
it's not very common now with http/2 but it's a good thing too track to understand bad behaviors