[Feature Request] PageStackNavController: events that trigger when pushing a page to an empty stack or when stack is cleared

[capdiem]

Proposal and motivation

We would like an event that triggers when the first page is pushed onto the stack and when the last page is removed from the stack (including when the stack is cleared), so that we can update the state of the returned tab.

Additional context

public class StackChangedEventArgs: EventArgs {
    public int Count { get; set; } // latest length of stack
    public string Action { get; set; } // push,pop,clear?
    public string AbsolutePath { get; set; }
}

public EventHandler<StackChangedEventArgs>? StackChanged;

PageStackNavController.StackChanged += OnPageStackNavControllerStackChanged;