I/O vs CPU-intensive tasks

As you know now, what you normally write are called non-leaf futures. Let’s take a look at this async block using pseudo-Rust as an example:

let non_leaf = async {
    let mut stream = TcpStream::connect("127.0.0.1:3000").await.unwrap();
    // request a large dataset
    let result = stream.write(get_dataset_request).await.unwrap();
    // wait for the dataset
    let mut response = vec![];
    stream.read(&mut response).await.unwrap();
    // do some CPU-intensive analysis on the dataset
    let report = analyzer::analyze_data(response).unwrap();
    // send the results back
    stream.write(report).await.unwrap();
};

I’ve highlighted the points where we yield control to the runtime executor. It’s important to be aware...