Convert a Stream that emits Streams (aka a 'Higher Order Stream') into a single Stream that emits the items emitted by the most-recently-emitted of those Streams.
This Stream will unsubscribe from the previously-emitted Stream when a new Stream is emitted from the source Stream and subscribe to the new Stream.
final switchLatestStream = SwitchLatestStream<String>( Stream.fromIterable(<Stream<String>>[ Rx.timer('A', Duration(seconds: 2)), Rx.timer('B', Duration(seconds: 1)), Stream.value('C'), ]), ); // Since the first two Streams do not emit data for 1-2 seconds, and the // 3rd Stream will be emitted before that time, only data from the 3rd // Stream will be emitted to the listener. switchLatestStream.listen(print); // prints 'C'
static Stream<T> switchLatest<T>(Stream<Stream<T>> streams) => SwitchLatestStream<T>(streams);