How to Use Async Iterators (Streams) in Rust

Use the async keyword to define a function that returns a Future and await to pause execution until the result is ready.

use trpl::Html;

async fn page_title(url: &str) -> Option<String> {
    let response_text = trpl::get(url).await.text().await;
    Html::parse(&response_text)
        .select_first("title")
        .map(|title| title.inner_html())
}

This pattern allows you to chain asynchronous operations like fetching a URL and parsing HTML without blocking the thread.

Async iterators let your program start a task, pause while waiting for it to finish, and do other work in the meantime. Think of it like ordering coffee: you place the order, wait for the barista to call your name, and then pick it up, rather than standing there staring at the machine the whole time. This keeps your application responsive while handling slow operations like network requests.