Flag for Span Links not working for Pulsar

[damienburke]

Describe the bug
The flag OTEL_INSTRUMENTATION_MESSAGING_EXPERIMENTAL_RECEIVE_TELEMETRY_ENABLED has no impact when publishing / consuming messages using Apache Pulsar

Steps to reproduce
Run an Apache Pulsar Producer and Consumer app and simply publish a message.

What did you expect to see?
With OTEL_INSTRUMENTATION_MESSAGING_EXPERIMENTAL_RECEIVE_TELEMETRY_ENABLED set to true, i would expect to see 2 traces, with a Span link.

What did you see instead?
I just see 1 trace though, for the send, receive and process spans.

What version are you using?
1.26.0 of Otel
Tested against v2.8.4 and 2.11.1. pulsar client.

Environment
Compiler: eclipse-temurin:17.0.7_7
OS: MacOS 13.4

Additional context
This is a very straight forward, happy path use case. My screen shot is of New Relic, which I am aware does not support Span Links. What I did though in addition, was compare the io.opentelemetry.exporter.logging.LoggingSpanExporter output, and they were "identical" for when the flag was true and false. Thanks

[trask]

cc @tjiuming

[tjiuming]

acked