Const ExperimentalIf the key type is not string, it's string representation has to be supplied for the attribute. If the key has no unambiguous, canonical string form, don't include its value.
This attribute is experimental and is subject to breaking changes in minor releases of @opentelemetry/semantic-conventions.
Message keys in Kafka are used for grouping alike messages to ensure they're processed on the same partition. They differ from
messaging.message.idin that they're not unique. If the key isnull, the attribute MUST NOT be set.