Android : Scrolling / sticky FAB floating action button android

I need to add a FAB to a scrolling page, however, I need, at a specific point on the screen, to have the FAB continue and scroll up with it, as it is not related to the content at the bottom of the page.

I'm thinking it will kind of work in reverse of a sticky view, which keeps scrolling until it hits the top, then stays there, this will stay at the bottom until a certain point in which it will scroll upwards and off screen.

I can't find this googling, and am thinking I'm going to have to somehow reverse one of the many sticky libraries out there, but they're pretty daunting for someone with limited custom view experience.