Bind local port for remote connection about kcp-go

[AudriusButkevicius]

This would be a breaking API change.

Just use NewConn(hostname:port, nil, 0, 0, your own provided PacketConn)

[AudriusButkevicius]

DialWithOptions takes a PacketConn as one of the arguments

[ValdikSS]

I mean https://github.com/xtaci/kcp-go/blob/master/sess.go#L914
Instead of "nil" in second argument there should be a way to specify source address and port.

[xtaci]

@ValdikSS use your own net.PacketConn will solve this .