Wherever delegate works block also works, but sometimes delegate is still a better choice in API design.

How do method lookup, dynamic resolution and message forwarding work together in objc_msgSend?

Code depending on the order of view transition events is dangerous for it is so inconsistent.

Rules to follow when designing initializers.

How to use UIViewController actor chain on iOS 8 and how it is implemented.

iWatch, no. iBand and new iPod, yes. iBud, maybe.

It is a common API design pattern. But how to do it in Swift is not well known.