protected void closeTable() {
      try {
        if (table != null) {
          table.close();
        }
      } catch (IOException e) {
        LOG.error("Error closing table", e);
      }
    }
@param readerId only the keys with this remainder from division by {@link #numThreads} will
                be read by this thread
hbase-diagnostics/src/main/java/org/apache/hadoop/hbase/util/MultiThreadedReader.java