streamDocumentsInCollection method
      
  
Stream<List<DocumentSnapshot> > 
streamDocumentsInCollection(
    
    
- CollectionReference reference
override
    Implementation
@override
Stream<List<DocumentSnapshot>> streamDocumentsInCollection(
        CollectionReference reference) =>
    reference._ref.snapshots().map((event) => event.docs
        .map((e) => DocumentSnapshot(
            _doc(this, e.reference), e.exists ? e.data() : null))
        .toList());