# Challenge: Create Async GooglyEyes | raywenderlich.com **URL:** \ **Category:** 🎓 Courses & Articles\ **Created:** [July 6, 2020, 2:54pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119 "2020-07-06T14:54:24Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![audrey](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/audrey/32/111607_2.png) [@audrey](https://forums.kodeco.com/u/audrey)\ **Post date:** [July 6, 2020, 2:54pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/1 "2020-07-06T14:54:24Z")
* * * This is a companion discussion topic for the original entry at [https://www.raywenderlich.com/9461083-ios-concurrency-with-gcd-and-operations/lessons/8](https://www.raywenderlich.com/9461083-ios-concurrency-with-gcd-and-operations/lessons/8) ---
**Author:** ![amurad](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/amurad/32/110937_2.png) [@amurad](https://forums.kodeco.com/u/amurad)\ **Post date:** [December 18, 2020, 12:33pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/2 "2020-12-18T12:33:25Z")
Hi Audrey I am wondering if creating a strong ref to weak self in closure capture list is necessary? is it only to get rid of question marks when using weak self within the closure? Many Thanks:) ---
**Author:** ![audrey](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/audrey/32/111607_2.png) [@audrey](https://forums.kodeco.com/u/audrey)\ **Post date:** [December 19, 2020, 1:43am UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/3 "2020-12-19T01:43:51Z")
hi Ahmad! it’s to make sure `self` still exists, in case the user has moved away from this view controller. Swift 5.3 removes the need to use `self.` in some closures. ---
**Author:** ![amurad](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/amurad/32/110937_2.png) [@amurad](https://forums.kodeco.com/u/amurad)\ **Post date:** [December 26, 2020, 5:36pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/4 "2020-12-26T17:36:25Z")
Many thanks Audrey 🙂 ---
**Author:** ![shrutisharma](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/shrutisharma/32/81494_2.png) [@shrutisharma](https://forums.kodeco.com/u/shrutisharma)\ **Post date:** [February 3, 2021, 11:08pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/5 "2021-02-03T23:08:23Z")
Hi Audrey Thank you for the tutorial. I have a question here. Is it required to call **self.fadeInNewImage(overlayImage)** in DispatchQueue.main since in the asyncGooglyEyes() we are calling the completion handler on the main queue itself. Thanks ---
**Author:** ![audrey](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/audrey/32/111607_2.png) [@audrey](https://forums.kodeco.com/u/audrey)\ **Post date:** [February 4, 2021, 12:56am UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/6 "2021-02-04T00:56:06Z")
hi Shruti! you’re right, the Main Thread Checker doesn’t complain when I comment out DispatchQueue.main in the completion handler. ---
**Author:** ![shrutisharma](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/shrutisharma/32/81494_2.png) [@shrutisharma](https://forums.kodeco.com/u/shrutisharma)\ **Post date:** [February 4, 2021, 3:40am UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/7 "2021-02-04T03:40:25Z")
Thank you Audrey for the prompt reply and clarification. Enjoying the tutorial! ---
**Author:** ![idcrook](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/idcrook/32/93524_2.png) [@idcrook](https://forums.kodeco.com/u/idcrook)\ **Post date:** [February 11, 2021, 8:51pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/8 "2021-02-11T20:51:27Z")
An observation that may help other who might encounter the same: the face features **`CIDetector`** is not working for me on a iPhone Simulator on an M1 Mac mini. It does work on an Intel Mac (2015 MBP) and on actual iOS devices. - iOS Device running iOS 14.4: **WORKS** - Xcode 12.4 / iOS 14.4 Sim / Intel Mac (macOS 11.2.1): **WORKS** - Xcode 12.4 / iOS 14.4 Sim / M1 Mac mini (macOS 11.2.1): **DOES NOT WORK** ---
**Author:** ![audrey](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/audrey/32/111607_2.png) [@audrey](https://forums.kodeco.com/u/audrey)\ **Post date:** [February 11, 2021, 9:20pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/9 "2021-02-11T21:20:02Z")
thanks David! I noticed this when I replied to Shruti from my M1, and discussed it with Caroline Begbie (Metal book author). We worked out the same conclusions, but then I forgot to post. Thanks so much for your post! ---
**Author:** ![lucianboboc](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/lucianboboc/32/111788_2.png) [@lucianboboc](https://forums.kodeco.com/u/lucianboboc)\ **Post date:** [July 4, 2022, 1:44pm UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/10 "2022-07-04T13:44:32Z")
Hi Audrey, Not sure why when calling asyncGooglyEyes, inside the block you dispatch fadeInNewImage on main thread. Isn’t the block already on main thread? ---
**Author:** ![audrey](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/audrey/32/111607_2.png) [@audrey](https://forums.kodeco.com/u/audrey)\ **Post date:** [July 5, 2022, 5:38am UTC](https://forums.kodeco.com/t/challenge-create-async-googlyeyes-raywenderlich-com/114119/11 "2022-07-05T05:38:08Z")
hi Lucian, you’re right, but only because the default value of `completionQueue` is the main queue. I guess it’s just safer to maintain the habit of dispatching to main.