App is slow to navigate to First page (which acts as Splashscreen)

[HelenMamalaki]

On windows, the app is really slow to navigate to the app's first page, which is a blank screen with a logo on it which acts as a splash screen. So it's definitely not an issue with the page itself. I've put timestamps to examine where the hold up is and it seems to be between the Maui App class being initialised and the constructor of the first pages ViewModel being hit. What could be causing the delay? Sometimes our app can take up to 13seconds to load our 'splash screen' page on a low spec device!

Platform:

App start up timings on a high spec device with inter core i7 and 32GB RAM - performs significantly worse on low spec mobile tablets.

Windows App.xaml.cs: Initialising component: 10.53.14.50
Windows App.xaml.cs: Component initialised: 10.53.14.59
MauiProgram: Creating Maui App builder: 10.53.14.78
PrismStartup: Configure PrismAppBuilder: 10.53.14.82
PrismStartup: builder.CreateWindow complete: 10.53.14.96
MauiProgram: Maui App start building: 10.53.14.97
PrismStartup: Start of registering dependencies: 10.53.15.04
PrismStartup: End of registering dependencies: 10.53.15.05
MauiProgram: Maui App build complete: 10.53.15.17
Maui App.xaml.cs: App is initialising: 10.53.15.19
Maui App.xaml.cs: App is initialised: 10.53.15.44
+ 2sec (+ 6 seconds on a low spec tablet)
LoadingPageVM: Initialised: 10.53.17.46
LoadingPageVM: Finished navigating: 10.53.17.48
LoadingPage.xaml.cs: Initialised: 10.53.17.55

[brianlagunas]

99.9% of the time, any performance issues while navigating is because of application code. For example, if using the IInitializeAsync interface and you are running an async/await code path where the navigation is waiting for your async code to finish before continuing the navigation.

[HelenMamalaki]

This is more in reference to PrismAppBuilder's CreateWindow() - rather than NavigationAsync. There's a delay between Prism's builder.Create Window being called and the VM constructor of the first page being hit. My first page is just a splashscreen so has very little XAML and no bindings. I am able to reduce the time gap to be negligible by removing the majority of the viewmodels and just leaving one. But I'm not sure what that means, if the problem is with Maui, WinUI3 or Prism to be honest.

10.53.14.96: PrismStartup: builder.CreateWindow constructor hit:
.... + 3.5 sec wait
10.53.17.46: LoadingPageVM: Initialised:

The docs for Prism's CreateWindow say:
/// When the App is started and the native platform calls <see cref="IApplication.CreateWindow(IActivationState?)"/>
/// this delegate will be invoked to do your initial Navigation.