tokio_synchronous.rs

tokio_synchronous.rs

use std::error::Error;
use std::time::{Duration, Instant};
use tokio::net::TcpStream;
use tokio::prelude::*;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let now = Instant::now();

    task("task1", &now).await?;
    task("task2", &now).await?;
    task("task3", &now).await?;
    Ok(())
}

async fn task(label: &str, now: &std::time::Instant) -> Result<(), Box<dyn Error>> {
    println!("{} started: {:?}", label, now.elapsed());
    tokio::time::delay_for(tokio::time::Duration::from_secs(2)).await;
    let mut stream = TcpStream::connect("127.0.0.1:6142").await?;
    stream.write_all(label.as_bytes()).await?;

    println!("{} written: {:?}", label, now.elapsed());
    let mut buffer = [0; 5];
    stream.read_exact(&mut buffer).await?;
    stream.shutdown(std::net::Shutdown::Both)?;
    println!(
        "{} finished: {:?}",
        std::str::from_utf8(&buffer)?,
        now.elapsed()
    );
    Ok(())
}