4.x Provide a way to retrieve telemetry baggage from a `SpanContext` without having to start a `Span`

[tjquinno]

Environment Details

• Helidon Version: 4.x
• Helidon SE or Helidon MP
• JDK version:
• OS:
• Docker version (if applicable):

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Problem Description

The Helidon neutral tracing API provides access to baggage associated with a Span.

Sometimes, though, code has a SpanContext available (such as the one Helidon prepares for an incoming HTTP request) and for that code's purposes needs only the baggage, not an actual span.

The workaround is this:

SpanContext spanContext = // from somewhere
Span.Builder<?> b = tracer.spanBuilder("example");
Span span = b.parent(spanContext).start();
Optional<String> baggageValue = span.baggage("keyName");

This issue captures the request to add a way to retrieve baggage from a SpanContext without having to create a Span.