private ConsumerPartitionAssignor.Subscription subscriptionWithOwnedPartitions(
        List<TopicPartition> ownedPartitions,
        ConsumerPartitionAssignor.Subscription prevSubscription
    ) {
        return new ConsumerPartitionAssignor.Subscription(
            prevSubscription.topics(),
            null,
            ownedPartitions,
            DEFAULT_GENERATION,
            prevSubscription.rackId()
        );
    }
The assignment type is decided based on whether all the members are assigned partitions
for the first time (full), or incrementally when a rebalance is triggered.
jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/ClientSideAssignorBenchmark.java