This chapter covered a couple of slightly unusual examples that are possible with RxPHP, and which didn't fit into any of the previous chapters. These aren't things that we use on a daily basis, but it's good to know that features such as these are possible.
In particular, we went through the operators zip(), window(), materialize(), and dematerialize(). We saw how to propagate and handle errors in Observable chains and what role AutoDetachObserver has. Also, we compared the Observable::create() static method and the Subject class and when unsubscribing and completing an Observable chain. Apart from this, we created anonymous operators and wrote the DirectoryIteratorObservable class that recursively iterates a directory structure. Finally, we used RxPHP to make a simple FTP client that uses Observables for inputs and outputs.
In the last chapter, we're going to talk about implementations of Reactive Extension in languages other than PHP. Most notably, we'll have a look at RxJS-what...