public FlatMapSubjectBase(IPushObservable <TIn> sourceS, Func <TIn, CancellationToken, IPushObservable <TOut> > observableFactory) : base(sourceS.CancellationToken) { lock (_syncLock) { _outSubscriptions = CreateDisposableManagerInstance(); _observableFactory = observableFactory; _sourceSubscription = sourceS.Subscribe(OnSourcePush, OnSourceComplete, OnSourceException); } }