[Question] Relationship between "receive" and "process" spans in Kafka consumers

[vasilkosturski]

Context:
I'm implementing OpenTelemetry tracing for a Kafka-based system (using Python) and need clarification on how to structure spans correctly for a consumer.

• Kafka instrumentation auto-generates a receive span when the consumer picks up a message. This span is a child of the send span from the producer, though this is somewhat debatable as the proper producer->consumer relation seems to be FollowsFrom, done with a Link rather than ChildOf (see this issue for discussion). However, this is out of the scope of this question.

• I manually create a process span when processing the message.

Question:
Should process be a ChildOf receive, should it use FollowsFrom, or should they be independent siblings?

• ChildOf implies receive depends on process, but receive just marks message pickup from the Kafka broker. So it doesn't seem to be the right relation.
• FollowsFrom seems to make more sense as process always follows receive and receive is a prerequisite for process.
• Or should they be independent siblings under the send span from the producer? This would be the default behavior as receive is automatically generated by the instrumentation, and I'm manually creating the process span attaching the send context from the producer via the TraceContextTextMapPropagator.