This chapter described how to deal with two issues that can happen when writing an asynchronous application: dealing with CPU-intensive tasks and dealing with blocking tasks. Solutions to both problems can be handled via schedulers and two operators: subscribe_on and observe_on. Schedulers are objects that allow us to control on which execution context the ReactiveX operators will run. A chain of operators can use as many different execution contexts as needed.

Using schedulers allows us to keep a synchronous-like code style. With their API, it is possible to execute each operator of a chain on different threads. ReactiveX and RxPY provide a very developer-friendly syntax that makes multithreading easier to use than with most other libraries and frameworks.

The three schedulers that have been detailed in the second part of this chapter are the only ones that should be...