Ability to detect and abort page leave in app router.

[ken-spencer]

Goals

In my application, I have a requirement to warn a user if they are navigating away from a page if there are unsaved changes.

Non-Goals

Background

Previously I could accomplish this using the following features:
Router.events.on('routeChangeStart', routeChangeStart);
Router.router.abortComponentLoad();

Now that these are no longer availible, I am at a loss as to how to implement this feature. The useEffect solution mentioned in the manual does not allow me to stop a user from navigating away from the page.

Proposal

Can we restore the router events and abort for the app router? Or provide an alternative that can handle this use case?