For now the RTree from embedder is as close as we get to determine parts of platform views obscured by Flutter content. This can be revisited once framework has better support for providing hit test regions.

Alongside hit testing, mouse cursor switching needs to be supported. When cocoa view changes cursor it needs to be restored when user hovers Flutter content. Analogically, when cursor leaves Flutter content and hovers over platform view, the platform view cursor needs to be restored.