Fatal error: No observable object of type NavigationStack.Type found (iOS 13.0) about swiftui-navigation-stack HOT 5 CLOSED

import SwiftUI
import NavigationStack

struct ContentView : View {
    var body: some View {
        NavigationStackView {
            View1()
        }
    }
}

struct View1: View {
    var body: some View {
        ZStack {
            Color.green.edgesIgnoringSafeArea(.all)

            PushView(destination: View2()) {
                Text("PUSH")
            }
        }
    }
}

struct View2: View {
    @EnvironmentObject var navStack: NavigationStack

    var body: some View {
        ZStack {
            Color.yellow.edgesIgnoringSafeArea(.all)
            
            Button(action: {
                self.navStack.pop()
            }, label: {
                Text("POP")
            })
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

import SwiftUI
import NavigationStack

struct ContentView: View {

    @EnvironmentObject private var navigationStack: NavigationStack
    @ObservedObject private var viewModel = ContentViewModel()

    var body: some View {
        NavigationStackView(transitionType: .none) {
            viewModel.getContentView()
                .frame(minWidth: .zero, maxWidth: .infinity, minHeight: .zero, maxHeight: .infinity)
                .transition(.slide)
        }
    }
}

NavigationStackView(transitionType: .none) {
    viewModel.getContentView()
        .frame(minWidth: .zero, maxWidth: .infinity, minHeight: .zero, maxHeight: .infinity)
        .transition(.slide)
    }

struct MyRootView: View {
    var body: some View {
        NavigationStackView {
            ContentView()
        }
    }
}

struct ContentView : View {
    @EnvironmentObject private var navigationStack: NavigationStack
    @ObservedObject private var viewModel = ContentViewModel()

    var body: some View {
        viewModel.getContentView()
            .frame(minWidth: .zero, maxWidth: .infinity, minHeight: .zero, maxHeight: .infinity)
            .transition(.slide)
    }
}

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).

        // Create the SwiftUI view that provides the window contents.
        let contentView = NavigationStackView {
            ContentView()
        }

        // Use a UIHostingController as window root view controller.
        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        }
    }