async Task LoadUsersInCircle(int circle_id)
        {
            var list = await _mLearningService.GetUsersInCircle(circle_id);

            var userList = new List <user_by_circle_wrapper>();


            foreach (var item in list)
            {
                userList.Add(new user_by_circle_wrapper {
                    user = item
                });
            }

            UsersList     = new ObservableCollection <user_by_circle_wrapper>(userList);
            _tmpUsersList = UsersList;

            _user_image_manager.Clear();
            await   UpdateUserImages(0);
        }