https://blog.wongcw.com/2019/06/21/opensignal%e5%af%a6%e6%b8%ac%e9%9f%93%e5%9c%8b5g%e5%95%86%e7%94%a8%e7%b6%b2%ef%bc%9a%e4%b8%8b%e8%a1%8c%e5%9d%87%e9%80%9f%e5%83%85111mbps/