Add attribute http_route in metric http_client_request_duration_seconds_count

[Vinaum8]

Feature Request

Framework or library name: System.Net.Http
Library type: HTTP client

Is your feature request related to a problem?

Currently, the http_client_request_duration_seconds_count metric does not include the http.route attribute. This makes it difficult to analyze latency per logical route, especially in applications where multiple routes share the same host and HTTP method. It's frustrating not being able to clearly distinguish response times by route in observability tools like Grafana.

Describe the solution you'd like

Include the http.route attribute in the http_client_request_duration_seconds_count metric, similar to how it is already included in server-side instrumentation.

Describe alternatives you've considered

As a workaround, we have tried adding custom tags manually, but it defeats the purpose of auto-instrumentation and adds extra maintenance overhead.

Additional context

Adding http.route would improve consistency across client and server metrics and enhance the usability of dashboards that rely on route-level granularity.

[RassK]

@Vinaum8 shouldn't it be addressed in https://github.com/open-telemetry/opentelemetry-dotnet?

[RassK]

@Vinaum8 Sorry, I have old information, it's living now here
https://github.com/open-telemetry/opentelemetry-dotnet-contrib/tree/main/src/OpenTelemetry.Instrumentation.Http

so the maintaining repo is opentelemetry-dotnet-contrib