passing objects (e.g. `json::value`) to chained handlers: `route_params`, `route_data` and `session_data`

[MungoG]

[sgerbino]

Implemented in cppalliance/http: route_params carries params (captures), route_data (per-route datastore), and session_data (per-session datastore).

[vinniefalco]

Sounds like design decisions which need to be documented. Is there documentation?

[computerquip-work]

I'm not sure if intentional but it does seem like this clears session data per request: https://github.com/cppalliance/beast2/blob/develop/src/http_worker.cpp#L58

[vinniefalco]

Yep. I think there's supposed to be per-request data and per-session data. And I never figured out the API for that.