Bind ttorrent to network interface (e.g VPN only)

Thanks for all your work on ttorrent.
I would really like the ability to bind ttorrent downloads/uploads to a specific network interface (e.g VPN) and not transfer anything if that interface is down. I think Android 6 makes this much easier to do than in previous API levels.

Interface binding would also allow some really cool features like having the web interface available on the local wifi network to allow control from another device but do all downloading via a 4G connection or VPN (for some people with unlimited mobile data 4G is much faster than any available fixed broadband).

Ideally you could also add a feature to bring up a VPN automatically on app launch.

There is some info at the link below about binding to specific interfaces in andorid 5 and below:
http://stackoverflow.com/questions/2513713/how-to-use-3g-connection-in-android-application-instead-of-wi-fi