chatRepository method
Implementation
@override
ChatRepository? chatRepository(String? appId, String? roomId) {
var key = appId == null || roomId == null ? null : '$appId-$roomId';
if ((key != null) && (_chatRepository[key] == null)) {
_chatRepository[key] = ChatCache(ChatFirestore(
() => roomRepository(appId)!.getSubCollection(roomId!, 'chat'),
appId!));
}
return _chatRepository[key];
}