- What are the downsides of running certain code on the main thread?
a) It can block the UI.
- In which circumstances will threading not help your performance?
a) When you have a lengthy layout-related calculation.
- Which GCD feature can you use to execute an action when several other actions are done executing?
b) DispatchGroup.
- Which of the following is not a benefit of operations?
b) Faster code execution.
- What's the maximum number of Operations you can run at the same time?
a) There is no hard limit, iOS decides on the fly.
- What is KVO?
a) A way for objects to observe properties of another object.
- How do you start executing operations on an operation queue?
c) By adding operations to it.