OpenTelemetry metrics

Metrics for grpc are outlined [here](https://grpc.io/docs/guides/opentelemetry-metrics/)

Is there a reason why this has not been implemented?

Generally all languages follow a standardization, but it looks like [EventCounter](https://learn.microsoft.com/en-us/aspnet/core/grpc/diagnostics?view=aspnetcore-8.0#:~:text=Metrics%20is%20a%20representation%20of%20data%20measures%20over%20intervals%20of%20time%2C%20for%20example%2C%20requests%20per%20second.%20Metrics%20data%20allows%20observation%20of%20the%20state%20of%20an%20app%20at%20a%20high%20level.%20.NET%20gRPC%20metrics%20are%20emitted%20using%20EventCounter.) has been used instead

Start by comparing the gRPC OpenTelemetry metrics guide with the repository’s existing EventCounter-based metrics, whose implementation location is not identified in the issue. Determine the missing scope and expected metric behavior before proposing implementation, then validate the result against the documented standard.

Written by the indexing model from the issue text.