code: func (r IndentedJSON) Render(w http.ResponseWriter) error {
  	r.WriteContentType(w)
  	jsonBytes, err := json.MarshalIndent(r.Data, "", "    ")
  	if err != nil {
  		return err
  	}
  	_, err = w.Write(jsonBytes)
  	return err
  }
docs: // Render (IndentedJSON) marshals the given interface object and writes it with custom ContentType.