Most direct way to create OnCursorStay "event" in UI.

Is there a proper way to perform manual raycasts against UI elements?

Currently I'm implementing...

 IPointerEnterHandler, IPointerExitHandler

...and calling an OnEnter / OnExit method which helps track which UI Button element the user is highlighting with their cursor. (To achieve tooltip behavior, more or less.)

This seems to be rather failure-prone: I can easily perform mouse activities that fail to invoke the pointers events; most critically, the exit event. (My tooltips linger.) Losing application focus also seems to create a failed invocation.

This is very undesirable for me, so I'm seeking the most secure, stable way to create the equivalent of an OnStay behavior. I haven't had this specific desire before, so I'm a little lost.

Thanks!