Create buffer layers

[CarbonSDK]

Create a new off-screen buffer/layer and render it on- screen for each layer of children.

For instance:
if a "window" has 2 children, and those children each a a child, we would have 1 on-screen canvas, and 3 off screen buffers, one for the window, one for the windows children, and one for the childrens children.

In this way changes will not require a full screen re-draw.
While in a web based UI dirty rectangles might be OK with overlapping canvas elements. in the native OpenGL modules this will cause performance issues, hence the purposed solution above.