code: func (formatter *StandardFormatter) Format(record *Record) string {
  	var message string
  	now := time.Now()
  	if now.Sub(record.Time) <= tolerance {
  		message = record.Message
  	} else {
  		message = fmt.Sprintf("[%v] %v", record.Time.Format(formatter.TimeFormat), record.Message)
  	}
  	return fmt.Sprintf("[%v] %v %v", now.Format(formatter.TimeFormat), record.Level, message)
  }
docs: // Format constructs string for logging. Time of logging is added to log message.
  // Also, if time of logging is more then 100 miliseconds in the passt, both
  // times will be added to message (time when application sent log and time when
  // message was processed). Otherwise, only time of processing will be written.