Prevent passing hot observable to operators like Concat

[bordoley]

Need to do it via the type system, but strictly speaking they're not concatable because they are not cold.

Probably need to add a cold or is multicasted flag. They can be used endWith, but not startWith and the could be the first argument to concat but not the second.

[bordoley]

Applies to StreamLike, MulticastObservable, PauseableObsevable, PublisherLike, and any Observable produced by share().

[bordoley]

One good option is to limit concat to RunnableObservables.

[bordoley]

Though that kind of sucks because an observable had iterates through an async iterable or a promise IE. a deferred observable is safe.

[bordoley]

Fixed in the rewrite branch that will be merged soon