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: udp_server.rs
    path of file: ./repos/phaser/phaser/vendor/mio/examples
    
    the code of the file until where you have to start completion: // You can run this example from the root of the mio repo:
// cargo run --example udp_server --features="os-poll udp"
use log::warn;
use mio::net::UdpSocket;
use mio::{Events, Interest, Poll, Token};
use std::io;

// A token to allow us to identify which event is for the `UdpSocket`.
const UDP_SOCKET: Token = Token(0);

fn main() -> io::Result<()> {
    env_logger::init();

    // Create a poll instance.
    let mut poll = Poll::new()?;
    // Create storage for events. Since we will only register a single socket, a
    // capacity of 1 will do.
    let mut events = Events::with_capacity(1);

    // Setup the UDP socket.
    let addr = "127.0.0.1:9000".parse().unwrap();
    let mu
    
fn main() -> io::Result<()> {
    env_logger::init();

    // Create a poll instance.
    let mut poll = Poll::new()?;
    // Create storage for events. Since we will only register a single socket, a
    // capacity of 1 will do.
    let mut events = Events::with_capacity(1);

    // Setup the UDP socket.
    let addr = "127.0.0.1:9000".parse().unwrap();
    let mut socket = UdpSocket::bind(addr)?;

    // Register our socket with the token defined above and an interest in being
    // `READABLE`.
    poll.registry()
        .register(&mut socket, UDP_SOCKET, Interest::READABLE)?;

    println!("You can connect to the server using `nc`:");
    println!(" $ nc -u 127.0.0.1 9000");
    println!("Anything you type will be echoed back to you.");

    // Initialize a buffer for the UDP packet. We use the maximum size of a UDP
    // packet, which is the maximum value of 16 a bit integer.
    let mut buf = [0; 1 << 16];

    // Our event loop.
    loop {
        // Poll to check if we have events waiting for us.
        poll.poll(&mut events, None)?;

        // Process each event.
        for event in events.iter() {
            // Validate the token we registered our socket with,
            // in this example it will only ever be one but we
            // make sure it's valid none the less.
            match event.token() {
                UDP_SOCKET => loop {
                    // In this loop we receive all packets queued for the socket.
                    match socket.recv_from(&mut buf) {
                        Ok((packet_size, source_address)) => {
                            // Echo the data.
                            socket.send_to(&buf[..packet_size], source_address)?;
                        }
                        Err(e) if e.kind() == io::ErrorKind::WouldBlock => {
                            // If we get a `WouldBlock` error we know our socket
                            // has no more packets queued, so we can return to
                            // polling and wait for some more.
                            break;
                        }
                        Err(e) => {
                            // If it was any other kind of error, something went
                            // wrong and we terminate with an error.
                            return Err(e);
                        }
                    }
                },
                _ => {
                    // This should never happen as we only registered our
                    // `UdpSocket` using the `UDP_SOCKET` token, but if it ever
                    // does we'll log it.
                    warn!("Got event for unexpected token: {:?}", event);
                }
            }
        }
    }
}