add method
Add a new document to this collection with the specified data, assigning it a document ID automatically.
Implementation
Future<DocumentReference<T>> add(T data) async {
final firestoreData = _queryOptions.converter.toFirestore(data);
_validateDocumentData(
'data',
firestoreData,
allowDeletes: false,
);
final documentRef = doc();
final jsonDocumentRef = documentRef.withConverter<DocumentData>(
fromFirestore: _jsonConverter.fromFirestore,
toFirestore: _jsonConverter.toFirestore,
);
return jsonDocumentRef.create(firestoreData).then((_) => documentRef);
}