Is DispatchQueue.global(qos: .userInteractive).async same as DispatchQueue.main.async

Question

I was going through the tutorial : https://www.raywenderlich.com/148513/grand-central-dispatch-tutorial-swift-3-part-1

And came across the definition of QoS class

Answer 1

You can use DispatchQueue.global(qos: .userInteractive).async{} when you want to do something very fast in the background while the user is interacting with your app. This is rarely used because, as it has to happen so quickly, you probably can do it directly in the main queue.

You can check this lecture where this issue is quite clearly explained.