Document Classes ⇒ Hook for end of a Beamer frame

[hendrick]

I'm writing a package to work with Beamer. Is there a hook I can use to run code automatically at the end of every frame? Ideally, I'd like something like an "\AtEndFrame" command that would work analogously to the \AtEndDocument command.

(My code uses TikZ with overlays to draw automatically-generated, slide-specific material on top of each slide. I want TikZ to draw *on top* of the frame contents, so I believe my commands have to come after all the frame contents. I could probably achieve this by redefining the outer theme, but I want to write a .sty file that I can use with various themes.)

Thanks for any help you can give!