Unhandled exception crashes App, but only if originating from async method

[MrDeej]

Describe the bug

If and exception occurs in an async method (button click event for example). It cannot be handled by App.UnhandledException and it will crash the app.
If and exception occurs in an void method( button click event for examp). It can be be handled by App.UnhandledException.

Steps to reproduce the bug

1. Make a new WinUI Desktop App.
2. Upgrade nuget to WinUI 3 Preview v3
3. Subscribe to app unhandledexception:

public App()
        {
            this.InitializeComponent();
            this.UnhandledException += App_UnhandledException;
        }
        private void App_UnhandledException(object sender, Microsoft.UI.Xaml.UnhandledExceptionEventArgs e)
        {
            e.Handled = true;
        }

3. Make an Additional button in the UI.

private void myButton_Click(object sender, RoutedEventArgs e)
        {
            //this is catched in app unhandled exception
            throw new Exception("void");
        }
        private async void myButton1_Click(object sender, RoutedEventArgs e)
        {
            //this crashes app
            throw new Exception("Async void");
        }

Expected behavior

Both async and void method should route exception to UnhandledException in app.

Should never ever ever crash an app due to an unhandled exception. This makes a horrid user experience.

Screenshots

No response

NuGet package version

No response

Windows app type

• UWP
• Win32

Device form factor

Desktop

Windows version

May 2021 Update (19043)

Additional context

No response

[kmgallahan]

Related #6153

[Scottj1s]

This is more closely a duplicate of #5221

[sjb-sjb]

Here's another version, and as minimal as one can imagine. Use the "Blank App, Packaged (WinUI 3 in Desktop)" template with the Visual Studio configuration copied below. Edit the OnLaunched method in App.xaml.cs as follows:

protected override void OnLaunched(Microsoft.UI.Xaml.LaunchActivatedEventArgs args)
{
    this.UnhandledException += this.App_UnhandledException;
    throw new InvalidOperationException("test");
    //m_window = new MainWindow();
    //m_window.Activate();
}

private void App_UnhandledException(object sender, Microsoft.UI.Xaml.UnhandledExceptionEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("tested");
}

Expected: App_UnhandledException is invoked.

Actual: App_UnhandledException is not invoked, and the program crashes with the message "An unhandled Win32 exception occurred in [15028] Test.exe" in a window that asks you to attach a debugger.

--
Microsoft Visual Studio Community 2022
Version 17.2.0
VisualStudio.17.Release/17.2.0+32505.173
Microsoft .NET Framework
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