Flow

Flow in Android development is part of the Kotlin Coroutines library. It is a type that can emit multiple values sequentially, making it perfect for working with any data streams or any streams of events that aren't instantaneous. Like Observables, Flow is also based on the observer pattern, meaning it can emit values and these emissions can be observed and reacted to. However, Flow comes with built-in back pressure handling and the ability to transform, filter, or combine these flows in a sequence. Along with Coroutines, Flow encourages a more predictable and simplified concurrency design without callback hell problem.