TCP server with tokio::spawn

#[tokio::main]
async fn main() -> io::Result<()> {
    let listener = TcpListener::bind("127.0.0.1:6380").await?;
    println!("echo server listening on 127.0.0.1:6380");
    loop {
        let (socket, _addr) = listener.accept().await?;
        tokio::spawn(async move { let _ = handle_conn(socket).await; });
    }
}

async fn handle_conn(mut socket: TcpStream) -> io::Result<()> {
    let mut buf = [0u8; 4096];
    loop {
        let n = socket.read(&mut buf).await?;
        if n == 0 { return Ok(()); }
        socket.write_all(&buf[..n]).await?;
    }
}