How to use async closures

Use async closures by defining a closure with the async keyword and invoking it with .await to handle asynchronous operations inline.

let fetch_title = async |url: &str| {
    let text = trpl::get(url).await.text().await;
    trpl::Html::parse(&text)
        .select_first("title")
        .map(|t| t.inner_html())
};

let result = fetch_title("https://example.com").await;

This pattern allows you to capture variables from the surrounding scope while performing non-blocking I/O, such as fetching a webpage title using the trpl crate.

An async closure is a small, anonymous function that can pause and resume while waiting for slow tasks like network requests to finish. It lets you write compact code that handles these waits without freezing your entire program. Think of it like ordering food at a restaurant: you place the order and wait at the table, but the kitchen works on it in the background until it's ready.