BaggageSpanProcessor should use ExtendedSpanProcessor.onEnding()

[jameyg42]

Component(s)

processors

Is your feature request related to a problem? Please describe.

Because BaggageSpanProcessor runs onStart(), newly added included Baggage keys need to be manually added to the current Span.

Describe the solution you'd like

BaggageSpanProcessor should be modified to implement ExtendedSpanProcessor and included baggage keys should be added onEnding().

Describe alternatives you've considered

No response

Additional context

No response

[jkwatson]

@zeitlinger @MikeGoldsmith any thoughts?

[zeitlinger]

Yes, we should do that

[zeitlinger]

@jameyg42 turns out that this feature request violates best practices - see https://github.com/open-telemetry/opentelemetry-java-contrib/pull/1633#issuecomment-2578006789

I therefore propose to close this issue.