[写在前面](%E5%86%99%E5%9C%A8%E5%89%8D%E9%9D%A2.md) [整体结构](%E6%95%B4%E4%BD%93%E7%BB%93%E6%9E%84.md) [数据结构](%E6%95%B0%E6%8D%AE%E7%BB%93%E6%9E%84.md) [api](api.md) [扩展消息结构](%E6%89%A9%E5%B1%95%E6%B6%88%E6%81%AF%E7%BB%93%E6%9E%84.md) [聊天扩展及切换](%E8%81%8A%E5%A4%A9%E6%89%A9%E5%B1%95%E5%8F%8A%E5%88%87%E6%8D%A2.md) [事件](%E4%BA%8B%E4%BB%B6.md)