I tried following these instructions and now my Xcode just hangs. Think twice before you try it.

Thank you. I am finally able to carry on with my work thanks to this solution.

@Jstarks03049 is the real hero of this thread. I had tried everything. But changing my wifi to 2.4GHz actually did the trick. I'm using an Orbi router and what I actually needed to do was reduce the 5GHz transmit power to 25% in Advanced > Advanced Setup > Wireless Settings > Advanced Wireless Settings (5GHz 802.11a/n/ac) > Transmit Power Control. I was unconvinced this would do anything, but to my delight and surprise, the update started downloading immediately after doing this. Hopefully, this will help someone else in a similar situation.

Yes, that could be the situation. In which case it's quite disappointing that I will need to roll my own animations.

Even if it is executed immediately it should be no different than executing it in the didDeselect method as demonstrated in the example. Surely, having the deselect in the async block would execute it at least one frame after it was scheduled?