encodeTopicPartitions = ({ topic, count, assignments = [] }) => {
  return new Encoder()
    .writeString(topic)
    .writeInt32(count)
    .writeNullableArray(assignments.map(encodeAssignments))
}
CreatePartitions Request (Version: 0) => [topic_partitions] timeout validate_only
  topic_partitions => topic new_partitions
    topic => STRING
    new_partitions => count [assignment]
      count => INT32
      assignment => ARRAY(INT32)
  timeout => INT32
  validate_only => BOOLEAN