Tracing through Channel

[Harwayne]

Problem
A request made to the Channel should generate traces that link the request to the subscribers. It should either use an existing Trace if present, or create a new Trace if one isn't.

The trace from the Channel to any subscribers MUST be annotated with the subscription's name.

Persona:
System Integrator

Exit Criteria
Each of the following generate a trace that includes both the incoming request and the request to any subscribers. The trace from the Channel to any subscribers MUST be annotated with the subscription's name:

• A request sent to an Channel without any trace information.
• A request sent to an Channel with trace information in the HTTP headers (B3 format).
• A request sent to an Channel with trace information in the Cloud Event's traceparent attribute, but not in the HTTP headers.

Note that this is very similar to knative/eventing#1757

[n3wscott]

Requires work and testing for PullSubscription and Topic

[Harwayne]

/milestone v0.10.0

[knative-prow-robot]

@Harwayne: The provided milestone is not valid for this repository. Milestones in this repository: []

Use /milestone clear to clear the milestone.

In response to this:

/milestone v0.10.0

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[Harwayne]

/assign

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