feature request: user provided state in bankai SSR

[cdaringe]

problem

• i want to embed bankai in my server per question: proxy to api server in development server mode #398, but need the rendered route to be derived via external state (e.g. my user's state, owned by my session service)

discussion

• existing discussion here
  • maybe a e.on('prerender', (route, state, cb) => ()) API would fill the need?
• i also need a convention for hydrating that base state browser-side as well. maybe we can collab on this in tandem here?

🚞🚞🚞

[goto-bus-stop]

choo reads state from the window.initialState variable, so we can output code for that in bankai.

[cdaringe]

neat-o. let's move the convo over to #413!