void prepare(Map<String, Object> conf, IMetricsContext metrics, int partitionIndex, int numPartitions) {
        this.options.prepare(conf, partitionIndex, numPartitions);
        initLastTxn(conf, partitionIndex);
    }
@Test
    public void testPrepare() {
        HdfsState state = createHdfsState();
        Collection<File> files = FileUtils.listFiles(new File(TEST_OUT_DIR), null, false);
        File hdfsDataFile = Paths.get(TEST_OUT_DIR, FILE_NAME_PREFIX + "0").toFile();
        assertTrue(files.contains(hdfsDataFile));
    }