pub fn block<R>(

        &mut self,

        layout: Layout,

        add_contents: impl FnOnce(&mut Self) -> R,

    ) -> InnerResponse<R> {

        self.block_dyn(layout, Box::new(add_contents))

    }

    pub fn block_dyn<'a, R>(

        &mut self,

        layout: Layout,

        add_contents: Box<dyn FnOnce(&mut Self) -> R + 'a>,

    ) -> InnerResponse<R> {

        let mut child_ui = self.child_ui(self.area(), layout);

        let inner = add_contents(&mut child_ui);

        InnerResponse::new(inner, Response::default())

    }