How can I completely clear the asset memory?

Background: This is a simple visionOS empty application. After the app launches, the user can enter an ImmersiveSpace by clicking a button. Another button loads a 33.9 MB USDZ model, and a final button exits the ImmersiveSpace.

Below is the memory usage scenario for this application:

1. After the app initializes, the memory usage is 56.8 MB.
2. After entering the empty ImmersiveSpace, the memory usage increases to 64.1 MB.
3. After loading a 33.9 MB USDZ model, the memory usage reaches 92.2 MB.
4. After exiting the ImmersiveSpace, the memory usage slightly decreases to 90.4 MB.

Question: While using a memory analysis tool, I noticed that the model's resources are not released after exiting the ImmersiveSpace. How should I address this issue?

struct EmptDemoApp: App {

    @State private var appModel = AppModel()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(appModel)
        }

        ImmersiveSpace(id: appModel.immersiveSpaceID) {
            ImmersiveView()
                .environment(appModel)
                .onAppear {
                    appModel.immersiveSpaceState = .open
                }
                .onDisappear {
                    appModel.immersiveSpaceState = .closed
                }
        }
        .immersionStyle(selection: .constant(.mixed), in: .mixed)
     }
}

struct ContentView: View {
    @Environment(AppModel.self) private var appVM
    
    var body: some View {
        HStack {
            VStack {
                ToggleImmersiveSpaceButton()
            }
            
            if appVM.immersiveSpaceState == .open {
                Button {
                    Task {
                        if let url = Bundle.main.url(forResource: "Robot", withExtension: "usdz") {
                            if let model = try? await ModelEntity(contentsOf: url, withName: "Robot") {
                                model.setPosition(.init(x: .random(in: 0...1.0), y: .random(in: 1.0...1.6), z: -1), relativeTo: nil)
                                appVM.root?.add(model)
                                print("Robot: \(Unmanaged.passUnretained(model).toOpaque())")
                            }
                        }
                    }
                } label: {
                    Text("Add A Robot")
                }
            }
        }
        .padding()
    }
}

struct ImmersiveView: View {
    @Environment(AppModel.self) private var appVM

    var body: some View {
        RealityView { content in
            appVM.root = content
        }
    }
}

struct ToggleImmersiveSpaceButton: View {
    @Environment(AppModel.self) private var appModel
    @Environment(\.dismissImmersiveSpace) private var dismissImmersiveSpace
    @Environment(\.openImmersiveSpace) private var openImmersiveSpace

    var body: some View {
        Button {
            Task { @MainActor in
                switch appModel.immersiveSpaceState {
                    case .open:
                        appModel.immersiveSpaceState = .inTransition
                        appModel.root = nil
                        await dismissImmersiveSpace()

                    case .closed:
                        appModel.immersiveSpaceState = .inTransition
                        switch await openImmersiveSpace(id: appModel.immersiveSpaceID) {
                            case .opened:
                                break

                            case .userCancelled, .error:
                                fallthrough
                            @unknown default:
                                appModel.immersiveSpaceState = .closed
                        }

                    case .inTransition:
                        break
                }
            }
        } label: {
            Text(appModel.immersiveSpaceState == .open ? "Hide Immersive Space" : "Show Immersive Space")
        }
        .disabled(appModel.immersiveSpaceState == .inTransition)
        .animation(.none, value: 0)
        .fontWeight(.semibold)
    }
}