The Future and Stream classes provide API for performing tasks, such as input/output, asynchronously, so as to avoid blocking your program. Futures and streams are fundamental to most Dart programs.

• The futures tutorial has been replaced by a codelab: Asynchronous programming: futures, async, await.
• The streams tutorial tells you how to use streams to manage sequences of data.

For a guided, hands-on introduction to Dart concepts, try one of the Dart codelabs.