HTTPCLIENT-2387: Micrometer/OTel observations & metrics (5.6)

[arturobernalg]

Add httpclient5-observation with timers/counters for classic/async, IO bytes, pool gauges, DNS/TLS meters; Observation interceptors; MetricConfig & options; offline tests; optional deps; Javadoc @SInCE 5.6; no-reflection pool binding.

[ok2c]

@arturobernalg This is a lot of code, but it plugs in quite nicely without leaking into the rest of the code base. If you are willing to maintain this code, and also prepared to work on the website content if you want this module to be visible at the project website.

[arturobernalg]

@arturobernalg This is a lot of code, but it plugs in quite nicely without leaking into the rest of the code base. If you are willing to maintain this code, and also prepared to work on the website content if you want this module to be visible at the project website.

@ok2c Absolutely. I’m willing to maintain this module long-term and keep its deps/tests healthy.
I’ll also prepare and maintain the website docs so it’s visible and properly documented.
If anything drifts, I’ll own the follow-ups across releases.