StartTestingClusterOption convert() {
    return StartTestingClusterOption.builder().numMasters(numMasters)
      .numAlwaysStandByMasters(numAlwaysStandByMasters).numRegionServers(numRegionServers)
      .rsPorts(rsPorts).numDataNodes(numDataNodes).dataNodeHosts(dataNodeHosts)
      .numZkServers(numZkServers).createRootDir(createRootDir).createWALDir(createWALDir).build();
  }
Convert to the internal option. Not for public use so package private.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/testing/TestingHBaseClusterOption.java