- ConnectWithConn wraps an existing net.Conn into a versioned proto.Conn
- DialFunc is a context-aware dial function type
- WithConn uses a pre-established net.Conn (version required, no DNS)
- WithDialer replaces net.Dialer with a custom dial function
- LoginRawAddr accepts an explicit handshake host address
- Login() wired to support all three connection modes