public ExpectableSubscriptionsWrapper(MarbleSpec spec, IExpectSubscriptions expectSubscriptions)
 {
     _spec = spec;
     _expectSubscriptions = expectSubscriptions;
 }
 public ExpectableObservableWrapper(MarbleSpec spec, IExpectObservable <T> expectObservable)
 {
     _spec             = spec;
     _expectObservable = expectObservable;
 }