stop main runloop to change the running order of progress indicator

progressIndicatorRunLoopPause.swift

func userDefaultsDidChange() {
    guard let controller = tableViewController else { return }
    
    let progressIndicator = { () -> NSProgressIndicator in
        let frame = view.frame
        let x = (frame.width - 50) / 2
        let y = (frame.height - 50) / 2
        let piFrame = NSMakeRect(x, y, 50, 50)
        let pi = NSProgressIndicator(frame: piFrame)
        pi.style = .spinningStyle
        
        return pi
    }()
    
    view.addSubview(progressIndicator)
    progressIndicator.startAnimation(self)
    
    RunLoop.main.run(until: Date(timeIntervalSinceNow: 0.001))
    
    controller.run()
    
    progressIndicator.stopAnimation(self)
    progressIndicator.removeFromSuperview()
}