Improve typesafety of Remote

[jedesah]

Currently, it is possible to create any kind of Remote. This is not too much of an issue because remotes should be generated by the macro most of the time. It might still be interesting to associate the creation of a Remote with it's environment and/or protocol in order to make manual creation more typesafe. It would also in theory make the macro implementation more fool proof (in theory).

It might also allow to more easily assert the fact that it is only possible to stream one stream per Remote call (if we decide to go down that route).