NetStream

The NetStream class opens a one-way streaming connection between a RTMP application and a RTMP server, or between a Flash Player or AIR application and the local file system. A NetStream object is a channel within a NetConnection object. This channel can either publish a stream, using NetStream.publish(), or subscribe to a published stream and receive data, using NetStream.play(). You can publish or play live (real-time) data and previously recorded data. You can also use NetStream objects to send text messages to all subscribed clients using the NetStream.send() method.

See the  Flex docs for more info.