Method update

examples/bad_apple.rs:87–114

(&mut self, message: Message, now: Instant)

    }

    fn update(&mut self, message: Message, now: Instant) {
        match message {
            Message::PlotMessage(plot_msg) => {
                self.widget.update(plot_msg);
            }
            Message::Tick => {
                if self.frame_count == 0 {
                    return;
                }
                let elapsed = match self.last_tick {
                    Some(prev) => now.saturating_duration_since(prev),
                    None => Duration::ZERO,
                };
                self.last_tick = Some(now);
                self.accumulator += elapsed;

                let mut steps = 0usize;
                while self.accumulator >= self.frame_duration {
                    self.accumulator -= self.frame_duration;
                    steps += 1;
                }
                if steps > 0 {
                    self.frame_idx = (self.frame_idx + steps) % self.frame_count;
                    self.update_frame();
                }
            }
        }
    }

    fn update_frame(&mut self) {
        if self.frame_count == 0 {