OperationQueue, we will see another way to perform concurrency in iOS.
OperationQueue is a higher-level abstraction of the queue model; on the other hand, GCD is a lower-level C API.
OperationQueue is built on top of GCD but in a more object-oriented fashion. In this section, we will perform the same demo but with
OperationQueue, and we will see how simple it is, as with GCD.
Before getting started with
OperationQueue, let's talk about how it is different from GCD: