@brief \b Producer: Set partitioner callback in provided topic conf object.
The partitioner may be called in any thread at any time,
it may be called multiple times for the same message/key.
Partitioner function constraints:
- MUST NOT call any rd_kafka_*() functions except:
rd_kafka_topic_partition_available()
- MUST NOT block or execute for prolonged periods of time.
- MUST return a value between 0 and partition_cnt-1, or the
special \c RD_KAFKA_PARTITION_UA value if partitioning
could not be performed.
@brief \b Producer: Set partitioner callback in provided topic conf object.
The partitioner may be called in any thread at any time, it may be called multiple times for the same message/key.
Partitioner function constraints: - MUST NOT call any rd_kafka_*() functions except: rd_kafka_topic_partition_available() - MUST NOT block or execute for prolonged periods of time. - MUST return a value between 0 and partition_cnt-1, or the special \c RD_KAFKA_PARTITION_UA value if partitioning could not be performed.