onChange property
Stream of record of Change
s of value
Implementation
Stream<Change<T>> get onChange {
_curBatch++;
final ret = StreamController<Change<T>>();
ret.add(Change<T>(value, value, _curBatch));
ret.addStream(_onChange.skipWhile((v) => v.batch < _curBatch));
return ret.stream.asBroadcastStream();
}