In my experience, most of the developers despite junior or senior are struggling to move with reactive programming. even they succeed they have no idea why they doing it and why that concept invented… what problem it solves.. this video is beginning to explain that. In reactive programming, data streams are going to be the base of your application. Events, messages, calls, and even failures are going to be conveyed by a data stream. With reactive programming, you observe these streams and react when a value is emitted.