private void updateLastSeenEpochIfNewer(TopicPartition topicPartition, OffsetAndMetadata offsetAndMetadata) {
        if (offsetAndMetadata != null)
            offsetAndMetadata.leaderEpoch().ifPresent(epoch -> metadata.updateLastSeenEpochIfNewer(topicPartition, epoch));
    }
Release the light lock protecting the consumer from multi-threaded access.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/ClassicKafkaConsumer.java