https://blog.wongcw.com/2021/09/29/%e4%ba%9e%e9%a6%ac%e9%81%9c-mmo%e3%80%8a-%e6%96%b0%e4%b8%96%e7%95%8c%e3%80%8b%e9%a6%96%e7%99%bc%e7%95%b6%e5%a4%a9%e7%aa%81%e7%a0%b4-70-%e8%90%ac%e7%8e%a9%e5%ae%b6/