Workaround for SFSafariViewController quick swipe bug. (https://openradar.appspot.com/23871289)

sfsafariviewcontroller_workaround.swift

let viewController = SFSafariViewController(URL: url)
presentViewController(viewController, animated: true) {
	
	for view in viewController.view.subviews {

		if let recognisers = view.gestureRecognizers {
			
			for gestureRecogniser in recognisers where gestureRecogniser is UIScreenEdgePanGestureRecognizer {

				gestureRecogniser.enabled = false
			}
		}
	}
}