SwiftUI: How to make Collapsible List?

Xcode12-iOS14

In WWDC20, Apple added another great feature in SwiftUI. It enables us to create collapsible list in less than 20 line. All we need to do is create a List with children like following:

📌 Please note: The child and root of a list should either be same class/struct or they must confront same protocol used to render list.