code: @Override
    public DataOutputStream create(final String name) throws IOException {
      final String directoryPath = outputPath + Path.SEPARATOR + name;
      if (!fs.exists(new Path(directoryPath))) {
        fs.mkdirs(new Path(directoryPath));
      }
      return fs.create(new Path(directoryPath + Path.SEPARATOR + getTaskId()));
    }
docs: create a file output stream using the given name.
  The path of the file on HDFS is 'outputPath/name/taskId'.
  
  @param name name of the created output stream
  It is used as the name of the directory if the created output stream is a file output stream
  @return OutputStream to a file on HDFS. The path of the file is 'outputPath/name/taskId'
  @throws java.io.IOException