Tracing through Sequences

[Harwayne]

Problem
A request made to a Sequence should generate traces that link the request through all stages of the sequence and its reply (if present). It should either use an existing Trace if present, or create a new Trace if one isn't.

This should mostly be done by the underlying Channel, this issue is to verify it works as expected. And explore whether the spans should be annotated with something additional to ensure it is clear why the request is being made.

Persona:
System Integrator

Exit Criteria
Each of the following generate a trace that includes the incoming request, every step in the sequence, and the request sent to the Sequence's reply. Every span within the trace must be identifiably associated with the Sequence.

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

Any Channel implementation may be used.

[Harwayne]

/project Observability To do

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