Distributed systems often utilize multithreading, event-based communication and nonblocking I/O to improve the overall system efficiency. These programming techniques impose challenges such as low-level threading, synchronization, thread safety, concurrent data structures, and non-blocking I/O. The open source ReactiveX library beautifully abstracts away these concerns, provides the required application plumbing, and extends the observable pattern on streams of asynchronous events. ReactiveX also has an active developer community and supports a growing list of languages, the most recent addition being RxSwift. It also implements binding to mobile and desktop platforms.
The reactive architecture keeps spreading across platforms and paradigms simply because it solves a common problem in an elegant way, hiding inevitable application plumbing in a nice encapsulation.