Task, отмена и группы задач

func compute17() async -> Int { 5 }
func start17() async -> Int {
    let task = Task { await compute17() * 2 }
    return await task.value
}

func loop17() async throws {
    for _ in 0..<10 {
        try Task.checkCancellation()
        await Task.yield()
    }
}

func square17(_ x: Int) async -> Int { x * x }
func all17() async -> [Int] {
    await withTaskGroup(of: Int.self) { group in
        for x in 1...3 { group.addTask { await square17(x) } }
        var out: [Int] = []
        for await value in group { out.append(value) }
        return out
    }
}

func child17() async -> Int { 1 }
func parent17() async -> Int {
    async let a = child17()
    return await a
}

actor Probe17 { var events: [String] = []; func add(_ e: String) { events.append(e) } }
func record17(_ probe: Probe17) async { await probe.add("done") }

func bad17() -> Int {
    let task = Task { 3 }
    return task.value
}

func endless17() async {
    while true {
        _ = 1 + 1
    }
}

func broken17() async -> () -> Void {
    await withTaskGroup(of: Int.self) { group in
        { group.addTask { 1 } }
    }
}

func fire17() {
    Task { try? await Task.sleep(for: .seconds(30)) }
}

func flaky17() async -> Bool {
    let task = Task { 1 }
    task.cancel()
    return await task.value == 0
}

func bad17() -> Int {
    let task = Task { 3 }
    return task.value
}

func endless17() async {
    while true {
        _ = 1 + 1
    }
}

func broken17() async -> () -> Void {
    await withTaskGroup(of: Int.self) { group in
        { group.addTask { 1 } }
    }
}

func fire17() {
    Task { try? await Task.sleep(for: .seconds(30)) }
}

func flaky17() async -> Bool {
    let task = Task { 1 }
    task.cancel()
    return await task.value == 0
}