https://blog.wongcw.com/2020/02/08/%e4%b8%80%e5%8f%b0a4%e7%b4%99%e4%bd%94%e5%9c%b0%e9%9d%a2%e7%a9%8d%e7%9a%84%e5%9f%ba%e5%9b%a0%e6%b8%ac%e5%ba%8f%e5%84%80sequencer%e6%88%96%e5%8f%af%e5%b9%ab%e5%8a%a9%e6%8a%97%e6%93%8a%e7%96%ab%e6%83%85/