Xamarin forms OnAppearing behaviour in iOS and android

I have noticed some difference in how the OnAppearing event behaves in iOS and android platforms.
1) The page is loaded before OnAppearing is hit in iOS whereas only after OnAppearing is executed the page is loaded in Android.
2) Coming from background all the OnAppearing's of pages in stack is hit for Android whereas for iOS none of the onAppearing events are hit.

Could help understand the actual behaviour of OnAppearing. Am I missing something.