Integration with OpenTelemetry, Prometheus, etc.

[achimnol]

In both PyCon US and KR talks, there were folks to suggest integration with OpenTelemetry.
https://opentelemetry.io/
https://opentelemetry.io/docs/instrumentation/python/
https://opentelemetry.io/docs/instrumentation/python/manual/

It would be nice to expose some basic metrics like the number of currently running tasks as telemetry stats.

Let's explore which metrics could be useful and how to expose them.

A QnA comment after PyCon APAC 2023 talk:

It would be nice if we could "tag" tasks and get statistics of task grouped by the same tag in metric monitoring systems.