NavigationService doesn't wait for the view to appear in ios

[abdomh]

🐛 Bug Report

in ios When navigating through navigation service to another view model the navigation will run and return before the navigation is completed, will also fire AfterNavigation Event before navigation has completed.

this happens because the code responsible for showing view model in MvxIosViewDispatcher doesn't know about the task being executed as it's action is stored in Action instead of Func<Task> which in turn results on an asynchronous execution

Expected behavior

When awaited it should not return until the navigation is completed

Reproduction steps

Navigate from ViewModelA to ViewModelB and do something after navigation it will execute before the navigation is completed in ios only

Configuration

Version: 6.x

Platform:

• 📱 iOS
• 🤖 Android
• 🏁 WPF
• 🌎 UWP
• 🍎 MacOS
• 📺 tvOS
• 🐒 Xamarin.Forms