hello_tcp.rs

use std::io;
use std::net::TcpListener;
use std::thread;

fn main() {
    let listener = TcpListener::bind("127.0.0.1:12345").unwrap();
    for stream in listener.incoming() {
        if let Ok(mut out) = stream {
            thread::spawn(move || {
                if let Ok(mut inp) = out.try_clone() {
                    let _ = io::copy(&mut inp, &mut out);
                }
            });
        }
    }
}

hello_tcp_client.rs

use std::io::{BufRead, BufReader, Write};
use std::net::TcpStream;

fn main() {
    let mut stream = TcpStream::connect("127.0.0.1:12345").unwrap();

    stream.write_all(b"Test\r\n").unwrap();

    let bufreader = BufReader::new(stream);
    for line in bufreader.lines().filter_map(Result::ok) {
        println!("{}", line)
    }
}