Async From First Principles

Your learning sequence

1. 1 Why async exists: blocking, threads, and the cost of waiting Read
2. 2 Not solved yet.○ Create, drop and run futures Practice · Easy
3. 3 Not solved yet.○ The Future trait: Output, Poll, and your first hand-written future Practice · Easy
4. 4 Not solved yet.○ block_on: poll a future to completion Practice · Easy
5. 5 Not solved yet.○ Countdown futures and the shape of Pending Practice · Easy
6. 6 Waker and Context: the wakeup contract Read
7. 7 Not solved yet.○ Queue another poll with Wake Practice · Medium
8. 8 Not solved yet.○ RawWaker and RawWakerVTable: building a Waker with unsafe Practice · Hard
9. 9 What async fn actually compiles to Read
10. 10 Pin and Unpin: keeping a value at a stable address Read
11. 11 Not solved yet.○ Unpin in practice: making Pin<&mut Self> usable without unsafe Practice · Medium
12. 12 Not solved yet.○ Hand-compile an async fn into a state machine Practice · Hard
13. 13 Not solved yet.○ poll_fn: a future from a closure Practice · Easy
14. 14 Not solved yet.○ Join two futures and keep both results Practice · Medium
15. 15 Not solved yet.○ Race two futures with a defined polling order Practice · Medium
16. 16 Not solved yet.○ Structural pinning and safe pin projection by hand Practice · Hard
17. 17 Not solved yet.○ The minimal single-threaded executor Practice · Hard
18. 18 Not solved yet.○ Spawning, JoinHandle, and getting values back out Practice · Hard
19. 19 Not solved yet.○ A logical-time reactor: timers without a clock Practice · Hard
20. 20 Not solved yet.○ Fairness and starvation in your scheduler Practice · Medium
21. 21 Not solved yet.○ Cancelling a future by dropping it Practice · Medium
22. 22 Not solved yet.○ Cancel safety, blocking, and locks across .await Practice · Hard
23. 23 Not solved yet.○ Async recursion, async closures, and streams Practice · Hard
24. 24 How tokio and smol build on these primitives Read
25. 25 Choosing between blocking and async code Read

fn calculate() -> u64 {
    (0u64..1_000_000)
        .map(|n| std::hint::black_box(n) * n)
        .sum()
}

async fn handler() -> u64 {
    calculate()
}