SwiftUI: EmptyView().onAppear {} formally exists, but not called when view is presented?

Question

SwiftUI:

EmptyView().onAppear {
//Not called
}

onAppear formally exists, but not called when view is presented?

Answer 1

Just simply add:

Rectangle()
   .hidden()
   .onAppear {
     // TODO: Do something
   }

Answer 2

Consider EmptyView is just as interface stub (to put something where view is required but at some moment there is nothing to provide). It is in a fact not inserted into view hierarchy, so .onAppear is not called, because nothing appears.