moveOverflowLayout method
Implementation
void moveOverflowLayout(Offset offset) {
  assert(_layoutOverflowRect != null, 'add overflow rect failed, _layoutOverflowRect not init');
  _layoutOverflowRect = _layoutOverflowRect!.shift(offset);
  assert(_visualOverflowRect != null, 'add overflow rect failed, _visualOverflowRect not init');
  _visualOverflowRect = _visualOverflowRect!.shift(offset);
}