How do you cancel a running `Task`?

Answer: Tasks support cooperative cancellation — you cancel from outside, and the task must check for cancellation and stop itself.

Code Example:

// Hold a reference to cancel it
let task = Task {
    for i in 0..<100 {
        try Task.checkCancellation()  // throws CancellationError if cancelled
        await processItem(i)
    }
}

// Cancel from outside
task.cancel()

// Checking cancellation without throwing
Task {
    while !Task.isCancelled {
        await doWork()
    }
}

// async APIs like URLSession respect cancellation automatically
Task {
    do {
        let (data, _) = try await URLSession.shared.data(from: url)
    } catch is CancellationError {
        print("Task was cancelled")
    }
}