public int partition(String topic, Object key, byte[] keyBytes, Object value, byte[] valueBytes, Cluster cluster) {
        return stickyPartitionCache.partition(topic, cluster);
    }
Compute the partition for the given record.

@param topic The topic name
@param key The key to partition on (or null if no key)
@param keyBytes serialized key to partition on (or null if no key)
@param value The value to partition on or null
@param valueBytes serialized value to partition on or null
@param cluster The current cluster metadata
clients/src/main/java/org/apache/kafka/clients/producer/UniformStickyPartitioner.java