Where does nginx.stubstatus.current get its data from?

Elastic Stack Beats
1

Looking at:
http://nginx.org/en/docs/http/ngx_http_stub_status_module.html

it says nothing about any metric in the stubstatus called "current", as listed here as "nginx.stubstatus.current":
https://www.elastic.co/guide/en/beats/metricbeat/current/exported-fields-nginx.html#_literal_nginx_stubstatus_current_literal

One could be tempted to think it came from "Active connections", but that does in fact already go into another field called nginx.stubstatus.active.

So how does nginx.stubstatus.current get populated and from which data?

Is it a derived metric?

2

current is a derived metric, it is the number of requests handled since the last metric fetch.

So the difference between the current nginx.stubstatus.requests and the previous.

3

Great - thanks!

Did I miss that in the docs somewhere?

I've searched high and low, and my last idea was actually to take a look at the source, but I thought it would be of greater public interest that I put the question in here, as the docs seems to be missing some details.