code: public static HdfsUnderFileSystem createInstance(AlluxioURI ufsUri,
        UnderFileSystemConfiguration conf, AlluxioConfiguration alluxioConf) {
      Configuration hdfsConf = createConfiguration(conf);
      return new HdfsUnderFileSystem(ufsUri, conf, hdfsConf, alluxioConf);
    }
docs: Factory method to constructs a new HDFS {@link UnderFileSystem} instance.
  
  @param ufsUri the {@link AlluxioURI} for this UFS
  @param conf the configuration for Hadoop
  @param alluxioConf Alluxio configuration
  @return a new HDFS {@link UnderFileSystem} instance