explanation.md

There is retain cycle between the Signal (a Signal is created when you start the producer, hence the name: SignalProducer) and the observer, when you use methods of the family start....

You have three ways to break this cycle:

• You dispose of the SignalProducer (if you notice, you get a Disposable, when you use a start...). You should avoid doing this, as it goes against RAC best practises
• You have a way to manipulate the SignalProducer. In your case you do have, by sending complete to the Observer.
• You use methods like take, takeWhile, until, which will terminate the SignalProducer. This is the prefered way.

Regarding the dispatch. Try this in your viewDidLoad:

timer(3, scheduler: QueueScheduler(name: "hello.scheduler")).map { _ in "hello" }.startWithNext { print($0) }

You will notice that although your viewDidLoad is long gone, it will still print "hello".