tokio超时取消函数调用

use futures::pin_mut;
async fn delay() {
    for i in 0..6 {
        tokio::time::sleep(std::time::Duration::from_secs(1)).await;
        println!("Ping! {}", i);
    }
}
async fn runner() {
    let delayer = delay();
    pin_mut!(delayer);
    if let Err(_) = tokio::time::timeout(std::time::Duration::from_secs(3), &mut delayer).await {
        println!("Taking more than three seconds");
        delayer.await;
    }
}