Observable<T>.concat constructor
Concatenates all of the specified stream sequences, as long as the previous stream sequence terminated successfully.
It does this by subscribing to each stream one by one, emitting all items and completing before subscribing to the next stream.
Example
new Observable.concat([
new Observable.just(1),
new Observable.timer(2, new Duration(days: 1)),
new Observable.just(3)
])
.listen(print); // prints 1, 2, 3
Implementation
factory Observable.concat(Iterable<Stream<T>> streams) =>
Observable<T>(ConcatStream<T>(streams));