Incorporating metrics from the threadpool

[davisjam]

This is a feature request, not a bug report. It is not currently actionable.

node-clinic currently gives great insight into the event loop. For some applications this is sufficient. For others, understanding the state of the threadpool may be crucial to tuning the threadpool size or the application behavior for best performance.

The threadpool has historically been hidden in libuv without a monitoring API (but see libuv #1528). I am trying to change this. I have proposed a libuv PR to make the libuv threadpool pluggable (libuv #1726) and a corresponding Node.js PR proposing various Node-land threadpools (Node.js #22631).

I would love to see threadpool monitoring integrated into node-clinic's offerings. To that end, I'd like to understand what kind of API and metrics you think would be beneficial. Please chime in on Node.js #22957 if you have thoughts.

[jasnell]

See libuv/libuv#1815 :-)

Currently it is blocked by (a) @bnoordhuis and (b) some rebasing and updating that I need to do.