async loading / code splitting tree sections

[arackaf]

@mweststrate asked me to open this, to aid in tracking.

Basically, I'm wondering (and eager) to know if there's a standard, built-in way to load a section of the tree on demand, like there is with Redux. Essentially, the ability to code split a section of the MobX state tree.

In Redux it looks like this

https://github.com/arackaf/booklist/blob/master/react-redux/applicationRoot/store.ts#L13-L16

[mattiamanzati]

Check #247 out

[mweststrate]

Closing for now, until more champions arrive