docs: @Override
      protected UniversalIdIntQueueMessage readFromQueueStorage(Connection conn) {
          Map<String, Object> dbRow = getJdbcHelper().executeSelectOne(conn, SQL_READ_FROM_QUEUE);
          if (dbRow != null) {
              UniversalIdIntQueueMessage msg = new UniversalIdIntQueueMessage();
              return msg.fromMap(dbRow);
          }
          return null;
      }