Before we consider adding concurrency to our application, we should make sure that we understand why we are adding it and ask ourselves whether it is necessary. While concurrency can make our application more responsive by offloading work from our main application thread to a background thread, it also adds extra complexity to our code and overhead to our application. I have even seen numerous applications, in various languages, which actually run better after we have pulled out some of the concurrency code. This is because the concurrency was not well thought out or planned. With this in mind, it is always a good idea to think and talk about concurrency while we are discussing the application's expected behavior.

At the start of this chapter, we had a discussion about running tasks concurrently compared to running tasks in parallel. We also discussed the hardware limitation that limits how many tasks can run in parallel on a given device. Having a good understanding of those concepts...