paint method
Draw itself and its children, according to the calculated
box.offset
Implementation
@mustCallSuper
void paint(Context context) {
  assert(() {
    if (Document.debug) {
      debugPaint(context);
    }
    return true;
  }());
}Draw itself and its children, according to the calculated
box.offset
@mustCallSuper
void paint(Context context) {
  assert(() {
    if (Document.debug) {
      debugPaint(context);
    }
    return true;
  }());
}