static void writeTestDataBatch(TableName tableName, int batchId) throws Exception {
    LOG.debug("Writing test data batch " + batchId);
    List<Put> puts = new ArrayList<>();
    for (int i = 0; i < NUM_ROWS_PER_BATCH; ++i) {
      Put put = new Put(getRowKey(batchId, i));
      for (int j = 0; j < NUM_COLS_PER_ROW; ++j) {
        put.addColumn(CF_BYTES, getQualifier(j), getValue(batchId, i, j));
      }
      put.setDurability(Durability.SKIP_WAL);
      puts.add(put);
    }
    try (Connection conn = ConnectionFactory.createConnection(conf);
      Table table = conn.getTable(tableName)) {
      table.put(puts);
    }
  }
A zero-based index of the current batch of test data being written
hbase-server/src/test/java/org/apache/hadoop/hbase/io/encoding/TestChangingEncoding.java