[Metrics API] Add support for histogram advice API

[lalitb]

Experimental histogram advice API to enable instrumentation library suggest histogram buckets - https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#instrument-advice

[marcalff]

Adding the breaking change label: this will require a new or changed API, hence changing the API ABI for metrics.

[github-actions]

This issue was marked as stale due to lack of activity.

[dufferzafar]

Is the Advice / Hints API still experimental? open-telemetry/opentelemetry-specification#2229

The go client already has support for it now: open-telemetry/opentelemetry-go#4605

[Falmarri]

The java client as well. Not really sure how to use histograms at all without that

[lalitb]

@Falmarri - The histogram buckets can be still configured using View API. Or let us know if you are looking for specific configuration from advisory API.

[Falmarri]

@lalitb Did I miss docs on this? Is there an example? This is using the sdk classes, right?

[lalitb]

Yes, there are unit-tests for custom buckets -

opentelemetry-cpp/sdk/test/metrics/histogram_test.cc

Line 78 in fabd8cc

TEST(Histogram, DoubleCustomBuckets)