Yes, thank you for clearing that confusion. I think I get it now. ps: async/await makes concurrency less complicated but it is still not trivial. 😢 also thank you for your remark about that adding a delete cache function requires a check.

Thank you for your help. Yes I was referring to that code that was posted to https://developer.apple.com/forums/thread/682032 (which was taken from the code section from the video of the "Developer" app where I was seeing it) You say "There's no suspension points between reading the current state and writing something based on that state." But: Reading state: if let cached = cache[url] { … } Suspension Point let handle = async { try await downloadImage(from: url) } Writing state: cache[url] = .inProgress(handle) Suspension Point: let image = try await handle.get() Writing state: Either cache[url] = .ready(image) or cache[url] = nil What if task 2 enters while task 1 is at the first suspension point, and therefore reads the cache still as nil? Is this some wrong thinking on my part? (Sorry) Does the task handle not count as suspension point?