Documentation could use note on how to loop background videos

[RamblinWreck77]

Wrestled with this for longer than I'd like to admit. Turns out background videos do not loop by default and none of the examples I found worked. The eventual solution was below (leaving the ? off moviePlayerController will throw an unexpected nil error):

Some type of .shouldLoopVideo = true/false would be a nice feature!

let vc = OnboardingViewController(backgroundVideoURL: generateVideo(file: "engineBackground"), contents: [firstPage, secondPage, thirdPage])!
vc.shouldBlurBackground = false
vc.shouldFadeTransitions = true
vc.swipingEnabled = true

NotificationCenter.default.addObserver(forName: .AVPlayerItemDidPlayToEndTime, object: vc.moviePlayerController?.player?.currentItem, queue: nil, using: { (_) in
DispatchQueue.main.async {
vc.moviePlayerController?.player?.seek(to: kCMTimeZero)
vc.moviePlayerController?.player?.play()
}
})

static private func generateVideo(file: String) -> URL {
let bundle = Bundle.main
let moviePath = bundle.path(forResource: file, ofType: "mp4")
let movieURL = URL(fileURLWithPath: moviePath!)
return movieURL
}