CreatableTopic convertToCreatableTopic() {
        CreatableTopic creatableTopic = new CreatableTopic().
            setName(name).
            setNumPartitions(numPartitions.orElse(CreateTopicsRequest.NO_NUM_PARTITIONS)).
            setReplicationFactor(replicationFactor.orElse(CreateTopicsRequest.NO_REPLICATION_FACTOR));
        if (replicasAssignments != null) {
            for (Entry<Integer, List<Integer>> entry : replicasAssignments.entrySet()) {
                creatableTopic.assignments().add(
                    new CreatableReplicaAssignment().
                        setPartitionIndex(entry.getKey()).
                        setBrokerIds(entry.getValue()));
            }
        }
        if (configs != null) {
            for (Entry<String, String> entry : configs.entrySet()) {
                creatableTopic.configs().add(
                    new CreatableTopicConfig().
                        setName(entry.getKey()).
                        setValue(entry.getValue()));
            }
        }
        return creatableTopic;
    }
The configuration for the new topic or null if no configs ever specified.
clients/src/main/java/org/apache/kafka/clients/admin/NewTopic.java