Book excerpt: Dive into Concurrency in iOS!Concurrency is the concept of multiple things, or pieces of work, running at the same time. With the addition of CPU cores in our devices, knowing how to properly utilize your customer's hardware to the maximum is absolutely a must. Unfortunately, proper concurrency in iOS apps is one of the lesser-known, lower-level topics, that every developer wants to (and should) understand properly, but is usually intimidated by.This is where Concurrency by Tutorials comes to the rescue! In this book, you'll learn everything there is to know about how to write performant and concurrent code for your iOS apps. Who This Book Is ForThis book is for intermediate iOS developers who already know the basics of iOS and Swift development but want to enrich their knowledge, learning more about how to efficiently perform tasks without affecting the performance of their app, and how to properly divide work to utilize hardware to the fullest extent.Topics Covered in Concurrency by TutorialsWhat & Why: Learn what is Concurrency and why would you even want to utilize it in your apps?Grand Central Dispatch: Learn about Apple's implementation of C's libdispatch, also known as GCD, it's one of the simplest ways to queue up tasks to be run in parallel.Operations & Operation Queues: When GCD doesn't quite cut it, you'll learn how to further customize and reuse your concurrent work using Operations and Operation Queues.Common Concurrency Problems: Learn about some of the problems you could face while developing concurrent applications, such as Race Conditions, Deadlocks, and more.Threads & Thread Sanitizer: Understand various threading-related concepts and how these connect to the knowledge you've accumulated throughout this book. You'll also learn how to use Thread Sanitizer to ease your debugging when things go wrong.This book is sure to make you a pro in building concurrent and performant applications, and finally understanding how these lower-level APIs work to the fullest, pushing your app to the top!