https://blog.wongcw.com/2020/02/28/%e7%be%8e%e5%9c%8b%e5%a4%96%e8%b3%a3%e5%85%ac%e5%8f%b8doordash%e6%ba%96%e5%82%99ipo-%e5%b7%b2%e5%90%91sec%e7%a7%98%e5%af%86%e6%8f%90%e4%ba%a4%e6%96%87%e4%bb%b6/