@Override
        public String toString() {
            return "Subscription(" +
                "topics=" + topics +
                (userData == null ? "" : ", userDataSize=" + userData.remaining()) +
                ", ownedPartitions=" + ownedPartitions +
                ", groupInstanceId=" + groupInstanceId.map(String::toString).orElse("null") +
                ", generationId=" + generationId.orElse(-1) +
                ", rackId=" + (rackId.orElse("null")) +
                ")";
        }
Unique name for this assignor (e.g. "range" or "roundrobin" or "sticky"). Note, this is not required
to be the same as the class name specified in {@link ConsumerConfig#PARTITION_ASSIGNMENT_STRATEGY_CONFIG}
@return non-null unique name
clients/src/main/java/org/apache/kafka/clients/consumer/ConsumerPartitionAssignor.java