code: func parseSlowLogFile(tz *time.Location, filePath string) ([][]types.Datum, error) {
  	file, err := os.Open(filePath)
  	if err != nil {
  		return nil, errors.Trace(err)
  	}
  	defer func() {
  		if err = file.Close(); err != nil {
  			logutil.Logger(context.Background()).Error("close slow log file failed.", zap.String("file", filePath), zap.Error(err))
  		}
  	}()
  
  	return ParseSlowLog(tz, bufio.NewScanner(file))
  }
docs: // parseSlowLogFile uses to parse slow log file.
  // TODO: Support parse multiple log-files.