code: private void loadBinlogFormat() {
          ResultSetPacket rs = null;
          try {
              rs = query("show variables like 'binlog_format'");
          } catch (IOException e) {
              throw new CanalParseException(e);
          }
  
          List<String> columnValues = rs.getFieldValues();
          if (columnValues == null || columnValues.size() != 2) {
              logger.warn("unexpected binlog format query result, this may cause unexpected result, so throw exception to request network to io shutdown.");
              throw new IllegalStateException("unexpected binlog format query result:" + rs.getFieldValues());
          }
  
          binlogFormat = BinlogFormat.valuesOf(columnValues.get(1));
          if (binlogFormat == null) {
              throw new IllegalStateException("unexpected binlog format query result:" + rs.getFieldValues());
          }
      }
docs: 获取一下binlog format格式