dark mode: update cgcolor when app is suspended

I'm facing trouble switching colours when change mode in iOS 13.

The problem is when you see the app in "recent apps view" (basically when you suspend your app). UIColors will change but cgColor will not change.

It will change effectively when you open the app (when your app is in foreground).

I'm using "traitCollectionDidChange" method as mentioned in following apple's document. https://developer.apple.com/documentation/xcode/supporting_dark_mode_in_your_interface

Please have a look at Video to understand more clearly

https://www.youtube.com/watch?v=C-pcVuPMQ9U&feature=youtu.be

class ViewController: UIViewController {

  @IBOutlet weak var viewColor: UIView!
  let layerColor = CALayer()

  override func viewDidLoad() {
       super.viewDidLoad()
       // Do any additional setup after loading the view.
       setLayer()
       setColors()
  }

  override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
       super.traitCollectionDidChange(previousTraitCollection)

       if traitCollection.hasDifferentColorAppearance(comparedTo: previousTraitCollection) {
            setColors()
       }
  }

  func setColors() {
       layerColor.backgroundColor = UIColor(named: "layerColor")?.cgColor
  }

  func setLayer() {
       layerColor.frame = CGRect(x: 0, y: 0, width: 40, height: 40)
       viewColor.layer.addSublayer(layerColor)
  }
}