public async Task <ActionResult <ToDoListResponse> > CreateOrUpdate(string identity, [FromBody] ToDoListRequest request) { var list = await _repository.GetListByIdentity(identity); if (list == null) { var record = await _repository.CreateList(ParseList(identity, request)); return(CreatedAtRoute("GetListByIdentity", new { identity }, ProjectList(record))); } else if (list.LastUpdateDateTime < request.UpdateDateTime) { ParseOntoList(request, list); await _repository.SaveChanges(); } return(ProjectList(list)); }