Asynchronous programming in Dart is characterized by the Future and Stream classes.

A Future represents a computation that doesn’t complete immediately. Where a normal function returns the result, an asynchronous function returns a Future, which will eventually contain the result. The future will tell you when the result is ready.

A stream is a sequence of asynchronous events. It is like an asynchronous Iterable—where, instead of getting the next event when you ask for it, the stream tells you that there is an event when it is ready.