Support multiple connection types

[WendelHime]

At lantern listener side (http-proxy), when we make a multiplex listener/wrap listeners, we return a custom connection type (idleConn - there's other custom connections/listeners under the same package, most of them are implementing net.Conn). As an WATER user I want to be able send a custom net.Conn and use this connection to successfully communicate.
Currently when I try to provide an idle connection I got the following error message:

ERROR water_plain_v1: water: PushConn: water: unsupported connection type: *listeners.idleConn 
2024/10/10 13:04:43 dial: v1net.Listener.Accept: errno 8

This message is being triggered here, falling into the default condition, since the custom connection is not supported.