AspNet HttpInListener OnStopActivity is called after Activity is stopped by TelemetryHttpModule

[jdaigle]

Bug Report

List of all OpenTelemetry NuGet packages and version that you are using (e.g. OpenTelemetry 1.0.2):

• OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule 1.0.0-rc9.3
• OpenTelemetry.Instrumentation.AspNet 1.0.0-rc9.3

Runtime version:

• net48

Symptom

The "OpenTelemetry.Instrumentation.AspNet.Telemetry" span is processed and exported before it can be enriched by the the HttpInListener and any custom Enrich callbacks.

What is the expected behavior?

For example, the DisplayName of the Activity should be set to the MVC Route instead of the raw URL.

What is the actual behavior?

The DisplayName of the Activity remains the raw URL

Additional Context

In https://github.com/open-telemetry/opentelemetry-dotnet/blob/1.0.0-rc9.3/src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs#L141, we can see that aspNetActivity.Stop(); is called before invoking the onRequestStoppedCallback. That callback is responsible for calling into OnStopActivity on HttpInListener which can update the name based on the route template can call the Enrich callback method.

I think that calling Stop() on the activity automatically triggers the ActivityListeners, including processors and exporters, to handle when the Activity is stopped.

Is it as simple as moving Stop() to after the callbacks?