code: func ServeJson(w http.ResponseWriter, v interface{}) {
  	content, err := json.MarshalIndent(v, "", "  ")
  	if err != nil {
  		http.Error(w, err.Error(), http.StatusInternalServerError)
  		return
  	}
  	w.Header().Set("Content-Length", strconv.Itoa(len(content)))
  	w.Header().Set("Content-Type", "application/json")
  	w.Write(content)
  }
docs: // Helper Functions to Write to the http.ReponseWriter -------------------------
  // ServeJson writes the JSON representation of resource v to the
  // http.ResponseWriter.