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: main.rs
    path of file: ./repos/ndi-router/src
    
    the code of the file until where you have to start completion: use tokio::net::{TcpListener, TcpStream};
use tokio::sync::{Mutex};
use tokio::stream::{Stream, StreamExt};
use tokio_util::codec::{Framed, LinesCodec, LinesCodecError};
use log4rs;
use futures::SinkExt;
use log::{error, info, debug};
use std::{env, error::Error, mem};
use std::sync::Arc;
use std::net::SocketAddr;
use std::pin::Pin;
use std::task::{Context, Poll};

mod ndi;
mod videohub;
mod peer;
mod shared;

use crate::videohub::{VideoHub};
use crate::peer::{Peer};
use crate::shared::{Shared};
use crate::ndi::{FindInstance, RouteInstance};

const VERSION: &'static str = env!("CARGO_PKG_VERSION");
const NUM_OUTPUTS: usize = 16;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    log4rs::ini
    
    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {

        if let Poll::Ready(Some(v)) = Pin::new(&mut self.rx).poll_next(cx) {
            return Poll::Ready(Some(Ok(Message::Broadcast(v))));
        }

        // Secondly poll the `Framed` stream.
        let result: Option<_> = futures::ready!(Pin::new(&mut self.lines).poll_next(cx));

        Poll::Ready(match result {
            // We've received a message we should broadcast to others.
            Some(Ok(message)) => {
                if message == "" {
                    Some(Ok(Message::Received(mem::replace(&mut self.buf, vec![]))))
                } else {
                    self.buf.push(message);
                    Some(Ok(Message::Received(vec!["None".to_owned()])))
                }
            },

            // An error occured.
            Some(Err(e)) => Some(Err(e)),

            // The stream has been exhausted.
            None => None,
        })
    }