Stream Stream.castFrom(source) Stream.empty(); Stream.error(error); Stream.eventTransformed(source, (sink) => null) Stream.fromFuture(future) Stream.fromFutures(futures) Stream.fromIterable(elements) Stream.multi((p0) { }) Stream.periodic(period) Stream.value(value) 9. periodic computation이 있어야합니다. 없으면 null이 나옵니다. void main(){ //Stream var computation = (x)=> x; var stream = Stream.periodic(cons..