Damien Mathieu

Your service has a lot of required context. A simpler reproduction case would help in helping you. This looks like a missmatch in the propagation headerd being used. Are you...

This is a rather large PR which, at a first glance, seems not to include only what's described in the PR title. Could it be split into smaller PRs?

+1 as well, for explicitness, but also consistency. When tracing mentions the context, we should also mention it for similar appropriate cases with other signals.

Each SDK uses this repository in their own way. [Go](https://github.com/open-telemetry/opentelemetry-proto-go) has a published module for example. In the case of javascript, the JS SDK has [this package](https://github.com/open-telemetry/opentelemetry-js/tree/main/experimental/packages/otlp-transformer) which holds a...

Or the README should be reworded.

Yes, metrics are stable now. So emitting one would be the way to go. Related (actually, both issues are duplicates): #5557.

You should write a [specification](https://github.com/open-telemetry/opentelemetry-specification/) change before this can be part of the stable API.

Similar solution for the otelhttp instrumentation: https://github.com/open-telemetry/opentelemetry-go-contrib/pull/5876

This should follow the same design as with the otelhttp `WithMetricAttributesFn` method. https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp#WithMetricAttributesFn

I'm unable to reproduce this running your sample example: > WARN [12:04:43] Failed to load config from file: /.env, Err: open /.env: no such file or directory INFO [12:04:43] Starting...