https://blog.wongcw.com/2020/02/21/edge-canary%e6%96%b0%e7%89%88%e5%b7%b2%e5%9c%a8%e5%b7%a5%e5%85%b7%e6%ac%84%e4%b8%8a%e6%96%b0%e5%a2%9e%e5%88%86%e4%ba%ab%e6%8c%89%e9%88%95/