Feature request: GetRoute

[szguoxz]

This is a very nice little package, but can we have a small feature? GetRoute(packet)

given a packet, can you return the route information?

Or to make it simple: GetRoute(src: SocketAddr, dest: SocketAddr)

I mean I need the route information for a packet, or a src/dst address pair with port information. As the kernel may need these information to match certain ip rules to apply certain routing tables.