[Zambyte]

This is really cool! I have been looking for something exactly like this. One point of feedback is that I noticed you use a sort of builder pattern by chaining methods to set certain fields on structs. Do you have a specific reason for doing that? I think it would be more idiomatic to just set the fields directly, overriding default values.

Another thing: have you played around with 0.16.0 at all yet? I think it's worth checking out if not. It'll have a lot of implications on what you're doing. If you want a hand on making a 0.16.0 branch, I'd be interested in helping out :)