consumer rebalancing

RU: ребалансировка consumer group

In Kafka, the process by which the group coordinator reassigns topic partitions across the active consumers in a consumer group. Triggered when a consumer joins or leaves, or when topic metadata changes. The classic eager protocol revokes all partitions before reassigning; the cooperative incremental protocol introduced in Kafka 2.4 moves only the partitions that need to change, letting unaffected consumers keep processing.