Hmm, I'm not totally sure why this is `/ (1 + rectPercentBuffer.bottom())`, that doesn't seem to get the expected result for me.

For example, say my width is 100, I have no constant buffer, and I have a 25% percent buffer on the top and bottom. I would expect this to return 50 as the child's width, but instead it would return 66.66667.

Also, why is this using `totalWidth - rectConstantBuffer.bottom()`? Shouldn't it be `totalWidth - rectContsantBuffer.right()`? Or am I totally misunderstanding how this code is supposed to work?