@Override
    public RecordReader<LongWritable, LongWritable> createRecordReader(InputSplit split,
      TaskAttemptContext context) throws IOException, InterruptedException {
      int taskId = context.getTaskAttemptID().getTaskID().getId();
      int numMapTasks = context.getConfiguration().getInt(NUM_MAPS_KEY, NUM_MAPS);
      int numIterations =
        context.getConfiguration().getInt(NUM_IMPORT_ROUNDS_KEY, NUM_IMPORT_ROUNDS);
      int iteration = context.getConfiguration().getInt(ROUND_NUM_KEY, 0);

      taskId = taskId + iteration * numMapTasks;
      numMapTasks = numMapTasks * numIterations;

      long chainId = ThreadLocalRandom.current().nextLong(Long.MAX_VALUE);
      chainId = chainId - (chainId % numMapTasks) + taskId; // ensure that chainId is unique per
                                                            // task and across iterations
      LongWritable[] keys = new LongWritable[] { new LongWritable(chainId) };

      return new FixedRecordReader<>(keys, keys);
    }
Modify table {@code getTableName()} to carry {@link SlowMeCoproScanOperations}.
hbase-it/src/test/java/org/apache/hadoop/hbase/mapreduce/IntegrationTestBulkLoad.java