So I'm trying to use the Body Motion Capture sample code provided by Apple. Not using storyboard. Using SwiftUI content View with a button to go to an ARView. The app builds fine but when I use the button to switch to ARView, im getting a runtime error. Any ideas out to fix this ? Thanks :) import UIKit import RealityKit import ARKit import Combine import SwiftUI import Foundation struct NavigationIndicator: UIViewControllerRepresentable {    typealias UIViewControllerType = ARVieww    func makeUIViewController(context: Context) -> ARVieww {       return ARVieww()    }    func updateUIViewController(_ uiViewController:    NavigationIndicator.UIViewControllerType, context:    UIViewControllerRepresentableContext) { } } class ARVieww: UIViewController, ARSessionDelegate {     var character: BodyTrackedEntity?     let characterOffset: SIMD3 = [0, 0, 0] // Offset the character by one meter to the left     let characterAnchor = AnchorEntity()          @IBOutlet var arView: ARView!          override func viewDidAppear(_ animated: Bool) {         print("yay")         super.viewDidAppear(animated)         arView.session.delegate = self                  // If the iOS device doesn't support body tracking, raise a developer error for         // this unhandled case.         guard ARBodyTrackingConfiguration.isSupported else {             fatalError("This feature is only supported on devices with an A12 chip")         }         // Run a body tracking configration.         let configuration = ARBodyTrackingConfiguration()         arView.session.run(configuration)                  arView.scene.addAnchor(characterAnchor)                  // Asynchronously load the 3D character.         var cancellable: AnyCancellable? = nil         cancellable = Entity.loadBodyTrackedAsync(named: "character/robot").sink(             receiveCompletion: { completion in                 if case let .failure(error) = completion {                     print("Error: Unable to load model: (error.localizedDescription)")                 }                 cancellable?.cancel()         }, receiveValue: { (character: Entity) in             if let character = character as? BodyTrackedEntity {                 // Scale the character to human size                 character.scale = [1.0, 1.0, 1.0]                 self.character = character                 cancellable?.cancel()             } else {                 print("Error: Unable to load model as BodyTrackedEntity")             }         })     }          func session(_ session: ARSession, didUpdate anchors: [ARAnchor]) {         for anchor in anchors {             guard let bodyAnchor = anchor as? ARBodyAnchor else { continue }                          // Update the position of the character anchor's position.             let bodyPosition = simd_make_float3(bodyAnchor.transform.columns.3)             characterAnchor.position = bodyPosition + characterOffset             // Also copy over the rotation of the body anchor, because the skeleton's pose             // in the world is relative to the body anchor's rotation.             characterAnchor.orientation = Transform(matrix: bodyAnchor.transform).rotation                 if let character = character, character.parent == nil {                 // Attach the character to its anchor as soon as                 // 1. the body anchor was detected and                 // 2. the character was loaded.                 characterAnchor.addChild(character)             }         }     }        }