throttle.dart

class Throttle<T> extends StreamEventTransformer<T,T> {
  final duration;
  Timer lastTimer;
	Throttle(millis) :duration = new Duration(milliseconds : millis);

	void handleData(T event, EventSink sink) {
	  if (lastTimer != null) {
	    lastTimer.cancel();
	  }
	  lastTimer = new Timer(duration, () => sink.add(event));
	}
}