The camera stuck for a moment

Code Block class ViewController: UIViewController {
   
  @IBOutlet var arView: ARView!
  fileprivate var configuration: ARWorldTrackingConfiguration!
  fileprivate var rootAnchor: AnchorEntity!
   
   
  // MARK: === viewWillAppear
  override func viewWillAppear(_ animated: Bool)
  {
    super.viewWillAppear(animated)
     
    configuration = ARWorldTrackingConfiguration()
    configuration.planeDetection = [.horizontal]
    arView.session.run(configuration)
  }
  // MARK: === viewDidLoad
  override func viewDidLoad() {
    super.viewDidLoad()
     
    arView.session.delegate = self
  }
}
// MARK: === ARSessionDelegate
extension ViewController: ARSessionDelegate
{
  func session(_ session: ARSession, didAdd anchors: [ARAnchor])
  {
    anchors.compactMap { $0 as? ARPlaneAnchor }.forEach {
      rootAnchor = AnchorEntity()
      rootAnchor.transform.matrix = $0.transform
      arView.scene.addAnchor(rootAnchor)
      add()
    }
  }
  // MARK: === add
  fileprivate func add()
  {
    guard let path = Bundle.main.path(forResource: "cupandsaucer", ofType: "usdz") else { return }
    var cancellable: AnyCancellable? = nil
    cancellable = ModelEntity.loadModelAsync(contentsOf: URL(fileURLWithPath: path)).sink(receiveCompletion: { error in
       
      cancellable?.cancel()
    }, receiveValue: { [self] modelEy in
       
      rootAnchor.addChild(modelEy)
      cancellable?.cancel()
    })
  }
}