private ConsumerPartitionAssignor.Subscription subscription(List<String> topics, int consumerIndex) {
        Optional<String> rackId = rackId(consumerIndex);
        return new ConsumerPartitionAssignor.Subscription(
            topics,
            null,
            Collections.emptyList(),
            DEFAULT_GENERATION,
            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