@Override
    public String toString() {
        return String.format("GroupMetadata(groupId = %s, generationId = %d, memberId = %s, groupInstanceId = %s)",
            groupId,
            generationId,
            memberId,
            groupInstanceId.orElse(""));
    }
A metadata struct containing the consumer group information.
Note: Any change to this class is considered public and requires a KIP.
clients/src/main/java/org/apache/kafka/clients/consumer/ConsumerGroupMetadata.java