I do not understand about WindowInsets rects, because docs says that:
The system window inset represents the area of a full-screen window that is partiall
There is only one type of WindowInsets which describes a set of insets for window content. since it is immutable and may be expanded to include more inset types in the future. you can create more instance of it. and you can also get the left,right etc insets of WindowInsets in pixels with methods like getStableInsetBottom() etc.