Telemetry tracking issue

[Mirko-von-Leipzig]

Tracking for follow-up tasks to the initial open-telemetry work in #660 #669 #675.

[sergerad]

@Mirko-von-Leipzig LMK if I could grab any of these

[Mirko-von-Leipzig]

@Mirko-von-Leipzig LMK if I could grab any of these

@sergerad the following are possible to implement:

• Custom span extension trait #678
• Instrument HTTP requests & responses #681
• Add system stats to telemetry #686

#679 is probably the most straight-forward, while the other two will likely require a bit of experimenting unless you're familiar with tower middleware and system stats (I'm not). Comment on any and I'll assign it to you :)

[sergerad]

Thanks @Mirko-von-Leipzig. Is #679 blocked by #583?

Either way I can look at #681 - I have been looking for an excuse to work with tower.