drawDRRect method
Draws a shape consisting of the difference between two rounded rectangles with the given Paint. Whether this shape is filled or stroked (or both) is controlled by Paint.style.
This shape is almost but not quite entirely unlike an annulus.
Implementation
void drawDRRect(RRect outer, RRect inner, Paint paint) {
assert(_rrectIsValid(outer));
assert(_rrectIsValid(inner));
assert(paint != null);
_drawDRRect(outer._value32, inner._value32, paint._objects, paint._data);
}