code: func (r Response) String() string {
  	ret := fmt.Sprintf("Request id: %s\n", r.ID)
  	if r.Receipt != "" {
  		ret += fmt.Sprintf("Receipt: %s\n", r.Receipt)
  	}
  	if r.Limit != nil {
  		ret += fmt.Sprintf("Usage %d/%d messages\nNext reset : %s",
  			r.Limit.Remaining, r.Limit.Total, r.Limit.NextReset)
  	}
  	return ret
  }
docs: // String represents a printable form of the response.