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/geph4-client/src/connect/tunnel
    
    the code of the file until where you have to start completion: 
use bytes::Bytes;

use derivative::Derivative;
use geph_nat::GephNat;
use parking_lot::RwLock;

use smol::channel::{Receiver, Sender};
use smol_str::SmolStr;
use std::{net::SocketAddr, ops::Deref};

use sosistab2::Stream;
use std::sync:
    
    pub async fn recv_vpn(&self) -> anyhow::Result<Bytes> {
        loop {
            let msg = self.recv_vpn_incoming.recv().await?;
            let status = self.connect_status.read();
            if let ConnectionStatus::Connected {
                protocol: _,
                address: _,
                vpn_client_ip: Some((_, nat)),
            } = status.deref()
            {
                if let Some(msg) = nat.mangle_downstream_pkt(&msg) {
                    return Ok(msg);
                }
            } else {
                anyhow::bail!(
                    "cannot processed received VPN when connection status is not connected"
                )
            }
        }
    }