Add support for Micrometer Observation

[marcingrzejszczak]

@blakeli0 suggested that I "move" the issue from googleapis/google-http-java-client#1868 (comment) over here.

We're more than happy to add support for instrumenting the Google Http Client with Micrometer Observation. If there's interest we can provide the PRs.

Initial PR to google client - googleapis/google-http-java-client#1879

[blakeli0]

@marcingrzejszczak Sorry if I didn't make it clear, we can keep all the discussion of adding Micrometer to google-http-java-client as they are. My suggestion was that, if you are interested in adding Micrometer to Google Cloud Client Libraries, this repo is the place to discuss it, and the discussion here would get more attention.

[marcingrzejszczak]

I see. Anyways, before I file a PR it would be good to know if there's any willingness to have the micrometer observation instrumentation added.