code: @Override
    public void initialize(
        InputSplit inputSplit, TaskAttemptContext taskAttemptContext) throws IOException {
      FileSplit fileSplit = (FileSplit)inputSplit;
      Configuration conf = taskAttemptContext.getConfiguration();
      Reader reader = OrcFile.createReader(
        fileSplit.getPath(),
        OrcFile.readerOptions(conf)
          .maxLength(OrcConf.MAX_FILE_LENGTH.getLong(conf))
          .filesystem(fileSplit.getPath().getFileSystem(conf)));
      Reader.Options options =
        OrcInputFormat.buildOptions(conf, reader, fileSplit.getStart(), fileSplit.getLength());
      recordReader = reader.rows(options);
    }
docs: Initialize ORC file reader and batch record reader.
  Please note that `initBatch` is needed to be called after this.