You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/tunshell/tunshell-server/src/relay/server
    
    the code of the file until where you have to start completion: use super::config::Config;
use crate::db::SessionStore;
use anyhow::{Error, Result};
use log::*;
use std::time::Instant;
use tokio::sync::mpsc;
use tokio
    
    fn handle_closed_waiting_connection(&self, closed: (Connection, Result<ClientMessage>)) {
        match closed {
            (_, Ok(msg)) => error!(
                "received unexpected message from client while waiting for peer: {:?}",
                msg
            ),
            (_, Err(err)) => error!(
                "connection error from client while waiting for peer: {:?}",
                err
            ),
        }
    }