https://blog.wongcw.com/2020/10/21/edge-canary%e6%96%b0%e5%8a%9f%e8%83%bd%ef%bc%9a%e5%8f%af%e9%87%8d%e7%bd%ae%e5%90%8c%e6%ad%a5%e6%95%b8%e6%93%9a/