Simple async example with Tokio

• We have function called do_something that fakes real work by sleeping a bit. It is marked as an async function.
• In the main function we setup the Runtime.
• Calling do_something() does not actually execute it. It returns a Future.

async fn do_something() {
    println!("Start to do something");
    tokio::time::sleep(tokio::time::Duration::from_secs(1)).await;
    println!("End   to do something");
}

fn main() {
    println!("Start");
    let rt = tokio::runtime::Runtime::new().unwrap();
    let future = do_something();

    println!("Before block");
    rt.block_on(future);

    println!("End");
}

[package]
name = "demo"
version = "0.1.0"
edition = "2024"

[dependencies]
tokio = { version = "1.39.2", features = ["full"] }

Start
Before block
Start to do something
End   to do something
End