Using stream controllers and sinks 

StreamControllers create a linked Stream and Sink. While streams contain data emitted sequentially that can be received by any subscriber, Sinks are used to insert events.

A stream controller simplifies stream management, automatically creating a stream and a sink, and methods to control their events and features.

In this recipe, you will create a stream controller to listen to and insert new events. This will show you how to fully control a stream.