Rust tokio demo of Notify usage

tokio_notify_demo.rs

use std::sync::Arc;
use tokio::sync::Notify;
use tokio::time::sleep;
use tokio::time::Duration;

// Notify can be thought of a Semaphore with 0 permits

async fn order_packages(package_delivered: Arc<Notify>) {
    sleep(Duration::from_secs(2)).await;
    println!("Company: Find package");

    sleep(Duration::from_secs(2)).await;

    println!("Company: Ship package");

    sleep(Duration::from_secs(3)).await;

    println!("Company: Package delivered");
    package_delivered.notify_one();
}

async fn grab_packages(package_delivered: Arc<Notify>) {
    println!("Buyer: Waiting for package");

    package_delivered.notified().await;

    println!("Buyer: Grab package");

    sleep(Duration::from_secs(3)).await;

    println!("Buyer: Package delivered");
}

#[tokio::main]
async fn main() {
    let package_delivered_arc = Arc::new(Notify::new());

    let order_packages_handle = tokio::spawn(order_packages(package_delivered_arc.clone()));

    let grab_packages_handle = tokio::spawn(grab_packages(package_delivered_arc.clone()));

    order_packages_handle.await.unwrap();
    grab_packages_handle.await.unwrap();
}

Output

Buyer: Waiting for package
Company: Find package
Company: Ship package
Company: Package delivered
Buyer: Grab package
Buyer: Package delivered