WebRTC conns are providing the correct IP for peer priority calculations, so use that instead of trying to guess (which doesn't work if there are no regular conn listeners attached to the Client.
(cherry picked from commit e86bb5fee3958dc90a3d012469b1352005d6c9ad)
Allow for certain values to always be properly initialized on construction -- namely the maps for now. I'm currently working on a change that requires a baseline constructor; this change would make the use of `chansync.BroadcastCond` and `chansync.SetOnce` obsolete -- i.e. one can have channel members without worrying about proper initialization/destruction of a `chan struct{}`.
As for why `makeClient` returns a value instead of a pointer: returning a value gives us more options -- you can always take a pointer from a value later on cheaply, and have things moved to the heap if they weren't already. The same can't be said about getting a value back from a pointer. GC also could potentially have less work to do. Plus I personally find ownership to be an important concept (semi-borrowed from rust) -- use of values make ownership clear.
Matt Joiner