This layout has been demonstrated at the end of Session 216 SwiftUI Essentials, but it didn't work in beta 1 and 2. In this beta 3, Apple secretly brought this layout to life (Not fully functional though).
NavigationLink("Go to detail", destination: Text("New Detail"))
Text("Placeholder for Detail")
I play around with
.navigationViewStyle and complex
destination's view, but can't make it work with a complex layout, it only supports very basic structure where the master view is a list and detail view is a leaf view. Maybe there is a way, but I will just wait for a proper document in the next release.