in flume-kafka-channel/src/main/java/org/apache/flume/channel/kafka/KafkaChannel.java [706:711]
public void onPartitionsRevoked(Collection<TopicPartition> partitions) {
for (TopicPartition partition : partitions) {
log.info("topic {} - partition {} revoked.", partition.topic(), partition.partition());
rebalanceFlag.set(true);
}
}