How do I use a callback to tell me that I've scrolled outside of fullpage?

### Description

I have tried "onleave", but it only seems to trigger if I am scrolling from one section to another. I need a callback to trigger if you leave the last slide and scroll past all the sections into the footer.

Here is a demo: https://codepen.io/kylerumble/pen/zYLxexB

You can see that the scrollbar is set to true. And I'd like to be able to know when the page is scrolled outside of the last slide.