code: func convertFields(fields logrus.Fields) map[string]string {
  	m := make(map[string]string)
  	for k, v := range fields {
  		switch t := v.(type) {
  		case time.Time:
  			m[k] = t.Format(time.RFC3339)
  		default:
  			if s, ok := v.(fmt.Stringer); ok {
  				m[k] = s.String()
  			} else {
  				m[k] = fmt.Sprintf("%+v", t)
  			}
  		}
  	}
  
  	return m
  }
docs: // convertFields converts from log.Fields to map[string]string so that we can
  // report extra fields to Rollbar