Features to consider adding to RRect:

• static zero
• left
• top
• right
• bottom
• xRadius
• yRadius
• width
• height
• shortestSide
• outerRect (bounding box)
• safeInnerRect (biggest rect entirely inscribed in rounded rect)
• somethingSomethingRect (the rect you get if you only use the flat sides of the rounded rect)
• size
• isEmpty
• isStadium (one or both sides has a radius half that side's dimension)
• isCircle (width and height are the same, both radii are greater than half the width or height)
• contains
• center
• inflate
• deflate
• lerp
• operator ==, hashCode
• toString