opt-in for enable_prometheus_metrics

[jhgoebbert]

I would suggest to change that to an opt-in.

At the moment jupyter-resource-usage is overloading tornado's task-pool for the prometheus-feature without taking into account that this will result in less (or even worst) performance for the critical webserver.

More details can be found here: #242

[jtpio]

Thanks @jhgoebbert.

Should the README also be updated to reflect the new default? https://github.com/jupyter-server/jupyter-resource-usage?tab=readme-ov-file#disable-prometheus-metrics

[jhgoebbert]

Hi @jtpio
I updated the README.md now too. Let me know if this would be fine for you:

---

There is a #123 with Prometheus metrics which causes "lag"/pauses in the UI. Hence, the Prometheus metric reporting is disabled by default (for all versions > 1.1.1).
If you want to use the Prometheus metric reporting you need to enable it with:

--ResourceUseDisplay.enable_prometheus_metrics=True

[jtpio]

Thanks, looks like the file needs a quick lint pass.

[jhgoebbert]

Hmm ... from the details I do not see that this is related to this PR.