My ViewModel

namespace FiberStarMobileApp.Core.ViewModels.AttendanceViewModels
{
    public class ListDetailAttendanceViewModel : BaseViewModel
    {
        private readonly IAttendanceService _service;
        private IMvxAsyncCommand _onCancelButtonCommand;

        public event PropertyChangedEventHandler PropertyChanged;

        HttpClient client = new HttpClient();
        private long _idItem;
        private MyModel _attend;
        private ImageSource _imgSelfieDetail;
        private bool _isLoadBusy = false;

        public ListDetailAttendanceViewModel(IMvxNavigationService navigationService, IAuthService authService, IAttendanceService service) : base(navigationService, authService)
        {
            _service = service;

            MessagingCenter.Unsubscribe<Pages.Attendance.ListAttendPage, long>(this, "OnItemSelected");
            MessagingCenter.Subscribe<Pages.Attendance.ListAttendPage, long>(this, "OnItemSelected", async (sender, value) =>
            {
                _idItem = value;
                await PerformShimmerAsyncTask(_idItem.ToString());
            });
        }

        public bool IsLoadBusy
        {
            get { return _isLoadBusy; }
            set
            {
                _isLoadBusy = value;
                OnPropertyChanged();
            }
        }

        public MyModel Attend
        {
            get { return _attend; }
            set { SetProperty(ref _attend, value); }
        }

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        public ImageSource ImgSelfieDetail
        {
            get { return _imgSelfieDetail; }
            set { _imgSelfieDetail = value; RaisePropertyChanged(() => ImgSelfieDetail); }
        }

        public IMvxAsyncCommand OnCancelButtonCommand => _onCancelButtonCommand ??
            (_onCancelButtonCommand = new MvxAsyncCommand(OnCancelButton));

        private async Task OnCancelButton()
        {
            await NavigationService.Close(this);
        }

        public async Task PerformShimmerAsyncTask(string id)
        {
            this.Attend = new MyModel
            {
                //Image = null,
                AddressDetail = "x",
                Created = DateTime.Now,
                Activity = "x",
                Note = "x"
            };

            this.IsLoadBusy = true;
            await Task.Delay(2500);
            this.IsLoadBusy = false;
            //await GetItem(id);

            this.Attend = new MyModel
            {
               Image = "selfie.png",
               AddressDetail = "asdasdasda",
               Created = DateTime.Now,
               Activity = "sadasdasdasfacf",
               Note = "asuuusfasfa"
            };
        }
    }


}