Experimental code to exit an iOS app.

ExitHandler.swift

    @IBAction func btnExit0Tapped (sender: UIButton) {
        exit(0) // Not recommended by Apple https://developer.apple.com/library/content/qa/qa1561/_index.html and app crashes
    }
    
    @IBAction func btnSuspendTapped (sender: UIButton) {
        UIControl().sendAction(#selector(URLSessionTask.suspend), to: UIApplication.shared, for: nil) // App exits gracefully
    }
    
    @IBAction func btnFatalErrorTapped (sender: UIButton) {
        fatalError() // App will crash
    }