Xamarin Forms + MvvmCross: how to clear the iOS and Android Navigation Stack? (custom presenters)

Hello,

On our iOS and Android apps we would like to clear the Navigation Stack in certain cases.

Searching around the Intertubes, I found a few articles:

http://gregshackles.com/presenters-in-mvvmcross-manipulating-the-back-stack/
http://gregshackles.com/presenters-in-mvvmcross-using-presentation-values/
http://stackoverflow.com/questions/17474865/mvvmcross-navigate-back-multiple-viewmodels-truncate-navigation-stack
http://slodge.blogspot.com/2013/06/presenter-roundup.html
https://gist.github.com/gshackles/5735595
https://github.com/ChristianRuiz/MvvmCross-ControlsNavigation
https://github.com/MvvmCross/MvvmCross-Tutorials/blob/master/Fragments/FragmentSample.UI.Droid/Setup.cs
http://stackoverflow.com/questions/22166869/how-to-hint-where-to-show-a-view-in-mvvmcross-with-splitview
http://enginecore.blogspot.com/2013/06/more-dynamic-android-fragments-with.html
https://canbilgin.wordpress.com/tag/mvxformsiospagepresenter/

I have a good idea that I need to do something like this -

var mvxBundle = new MvxBundle(new Dictionary<string, string> { { "NavigationCommand", "StackClear" } });
ShowViewModel<MyViewModel>(presentationBundle: mvxBundle);

And then I need to implement iOS and Android custom presenters that look for the "Clear" command above and clear the navigation stacks.

I'm using the out-of-the-box Xamarin Forms/MvvmCross presenters, here it is for iOS -

protected override IMvxIosViewPresenter CreatePresenter()
{
    Forms.Init();

    var xamarinFormsApp = new MvxFormsApp();

    return new MvxFormsIosPagePresenter(Window, xamarinFormsApp);
}

And here it is for Android -

protected override IMvxAndroidViewPresenter CreateViewPresenter()
{
    var presenter = new MvxFormsDroidPagePresenter();
    Mvx.RegisterSingleton<IMvxViewPresenter>(presenter);

    return presenter;
}

I'm having a hard time properly implementing the custom presenters for iOS and Android.

Does anyone know of a good example or can give me a hint on how to implement custom presenters to clear the iOS and Android navigation stacks in the context of Xamarin Forms + MvvmCross?

Thanks for any help!
@ehuna