Focus Follows Mouse

I am looking to see if there is a way to get a focus follows mouse behavior like in Unix.

I have been reading of some challenges with this, especially with regard to the global menu bar.

But I also saw some comments that maybe something could be addressed by adding a delay (e.g., the mouse has to stop moving and be within the window for a small period of time before that move would be seen as an actual placement of a mouse within a window that should be brought into focus. This delay would allow for the mouse to rapidly be moved to the menu bar to take action without screwing up the focus.

So from the short-delay perspective, the focus would simply be applied if the mouse was over that window for 1 second (for example).