private FSHLog createWAL() throws IOException {
    String logPrefix = factory.factoryId + WAL_FILE_NAME_DELIMITER + providerId;
    return new IOTestWAL(CommonFSUtils.getWALFileSystem(conf), CommonFSUtils.getWALRootDir(conf),
      AbstractFSWALProvider.getWALDirectoryName(factory.factoryId),
      HConstants.HREGION_OLDLOGDIR_NAME, conf, listeners, true, logPrefix,
      META_WAL_PROVIDER_ID.equals(providerId) ? META_WAL_PROVIDER_ID : null);
  }
@param factory    factory that made us, identity used for FS layout. may not be null
@param conf       may not be null
@param providerId differentiate between providers from one facotry, used for FS layout. may be
                  null
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/IOTestProvider.java