message: Fix custom widget example.
diff: @@ -39,10 +39,13 @@ mod circle {
  _renderer: &Renderer,
  _limits: &layout::Limits,
  ) -> layout::Node {
  - layout::Node::new(Size::new(
  + layout::Node::new(
  + Size::new(
  f32::from(self.radius) * 2.0,
  f32::from(self.radius) * 2.0,
  - ))
  + ),
  + Size::ZERO,
  + )
  }
  fn hash_layout(&self, state: &mut Hasher) {
  