Basic async proxy in Rust

proxy.rs

use std::time::Instant;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpListener;
use tokio::net::TcpStream;

#[tokio::main]
async fn main() {
    let listener = TcpListener::bind("0.0.0.0:9000").await.unwrap();
    loop {
        let (mut client, addr) = listener.accept().await.unwrap();
        println!("Client from {}", addr);

        let mut server = TcpStream::connect("0.0.0.0:8000").await.unwrap();
        println!("Server");

        let start = Instant::now();

        tokio::spawn(async move {
            match tokio::io::copy_bidirectional(&mut client, &mut server).await {
                Ok((to_egress, to_ingress)) => {
                    println!(
                        "Connection ended gracefully ({to_egress} bytes from client, {to_ingress} bytes from server)"
                    );
                }
                Err(err) => {
                    println!("Error while proxying: {:?}", err);
                }
            };

            println!("TOOK {}ms", start.elapsed().as_millis());
        });
    }
}