update comments, update go.mod check for register username

go.sum

@@ -15,8 +15,8 @@ cloud.google.com/go/storage v1.30.1 h1:uOdMxAs8HExqBlnLtnQyP0YkvbiDpdGShGKtx6U/o
 cloud.google.com/go/storage v1.30.1/go.mod h1:NfxhC0UJE1aXSx7CIIbCf7y9HKT7BiccwkR7+P7gN8E=
 firebase.google.com/go v3.13.0+incompatible h1:3TdYC3DDi6aHn20qoRkxwGqNgdjtblwVAyRLQwGn/+4=
 firebase.google.com/go v3.13.0+incompatible/go.mod h1:xlah6XbEyW6tbfSklcfe5FHJIwjt8toICdV5Wh9ptHs=
-github.com/AndrewZuo01/protocol v0.0.0-20231221102834-60b65871d305 h1:BhfGwZd7P0uUSoYv22UKGyeX8ci24vTaJXTRN/u/P54=
-github.com/AndrewZuo01/protocol v0.0.0-20231221102834-60b65871d305/go.mod h1:F25dFrwrIx3lkNoiuf6FkCfxuwf8L4Z8UIsdTHP/r0Y=
+github.com/AndrewZuo01/protocol v0.0.0-20231221110050-669939a050b4 h1:bJ5uiRu/plidSYZrq9Yu8PBw7DaNX/9qB2keQjM5hHU=
+github.com/AndrewZuo01/protocol v0.0.0-20231221110050-669939a050b4/go.mod h1:F25dFrwrIx3lkNoiuf6FkCfxuwf8L4Z8UIsdTHP/r0Y=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/IBM/sarama v1.41.3 h1:MWBEJ12vHC8coMjdEXFq/6ftO6DUZnQlFYcxtOJFa7c=
 github.com/IBM/sarama v1.41.3/go.mod h1:Xxho9HkHd4K/MDUo/T/sOqwtX/17D33++E9Wib6hUdQ=