Method update

examples/themes_and_styles.rs:44–55

(&mut self, message: Message)

    }

    fn update(&mut self, message: Message) {
        match message {
            Message::Plot(message) => self.widget.update(message),
            Message::ThemeSelected(theme_choice) => {
                self.theme_choice = theme_choice;
            }
            Message::StyleSelected(style_choice) => {
                self.style_choice = style_choice;
                self.widget.set_style(style_choice.style_fn());
            }
        }
    }

    fn view(&self) -> Element<'_, Message> {
        let toolbar = container(