chore: refactor module structure

src/message/server/message_user.rs

@@ -2,6 +2,7 @@ use crate::{
     message::{Message, MessageHandler},
     server::{ServerOperation, UserMessage},
 };
+use crate::{debug, error, info, trace, warn};
 use std::sync::mpsc::Sender;
 
 pub struct MessageUser;