Support OpenMetrics

[fengye87]

Looks like it's part of the coming-soon OpenMetrics. While prometheus/client_python has already had it, it's still missing here. Any plan to include it? I could author a PR if the answer is yes.

[beorn7]

OpenMetrics support is planned for v2. The OpenMetrics spec is not really done yet. The Python implementation is more a PoC of the current planning state.

I'll adjust the title here to mark things as such.

[beorn7]

Update: As things evolve, it will be really good to have OpenMetrics support in v1, too. Therefore, I created a milestone for that.

v2 will then certainly not kick out OpenMetrics support (but rather support it first class, if possible). Thus, I'm closing this as "implicitly given".