code: func (s *Service) Url(publicId string, rtype ResourceType) string {
  	path := imageType
  	if rtype == PdfType {
  		path = pdfType
  	} else if rtype == VideoType {
  		path = videoType
  	} else if rtype == RawType {
  		path = rawType
  	}
  	return fmt.Sprintf("%s/%s/%s/upload/%s", baseResourceUrl, s.cloudName, path, publicId)
  }
docs: // Url returns the complete access path in the cloud to the
  // resource designed by publicId or the empty string if
  // no match.