Allow pluggable Propagators for AspNetCore

[cijothomas]

Is your feature request related to a problem? Yes.

The issue is with the context propagation logic embedded within Asp.Net Core, HttpClient libraries. These libraries have a hard-coded propagation logic embedded inside them, which follows the W3CTraceContext protocol. However, this makes it hard for users who use non W3CTraceContext, as there is no way to "swap" the W3CTraceContext with something else.

Describe the solution you'd like

Let DiagnosticSource package expose a new Propagators API, ideally, in compliance with the OpenTelemetry specification for Propagators.. Here is the issue opened in runtime to track this - dotnet/runtime#46054
Once this API is exposed by the runtime, modify AspNetCore (and HttpClient) to simply use these new Propagators API. The default Propagator can be the W3CTraceContext one itself, to ensure backward compatibility. But users can swap it with any custom propagators they chose.

Additional context

Related issue: #27237
Runtime issue: dotnet/runtime#46054

[cijothomas]

@noahfalk @tarekgh @shirhatti

@alanwest @CodeBlanch from OpenTelemetry .NET group

[cijothomas]

@reyang

[tarekgh]

@cijothomas I think this will need to open another issue in the runtime repo and list there the complete proposal according the doc https://github.com/dotnet/runtime/blob/master/docs/project/api-review-process.md. you can then link this issue to the new one.

[cijothomas]

Thanks. Will open related issue in runtime repo as well!

[ghost]

Thanks for contacting us.
We're moving this issue to the Next sprint planning milestone for future evaluation / consideration. We will evaluate the request when we are planning the work for the next milestone. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[shirhatti]

This was completed by #33777