Should raise an error if no response method is called

```
async def post_record(http, stream, para):
    record = json.load(stream.data)
    # http.send_error(stream, 200)
```
Currently an end point function which doesn't call any response methods won't cause exceptions.

This function should cause an exception at the initialization time. That is, if the framework sees this, the app should not even start.