序列化类型编码使用rtti，提供替代方案

https://github.com/RFoe/coasync/blob/a466688370ce4bc5feefc8a55d960de447dfbfde/include/coasync/detail/meta/serde_stream_base.hpp#L163

## 或许是这样

```cpp
#if __cpp_rtti
std::type_index{ typeid(T) }.hash_code()
#else
static_hash<signature<T>()>()
#endif
```