async Task ConcertsTresholdReached()
        {
            if (IsBusy)
            {
                return;
            }

            IsBusy = true;

            try
            {
                pageNumber++;
                if (pageNumber > pagesCount)
                {
                    ConcertTreshold = -1;
                    return;
                }
                var concerts = await concertService.GetAllConcerts(pageNumber);

                Concerts.AddRange(concerts);
                FilteredConcerts.AddRange(concerts);
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
            }
            finally
            {
                IsBusy = false;
            }
        }
        async Task ExecuteLoadConcertsCommand()
        {
            if (IsBusy)
            {
                return;
            }

            IsBusy = true;

            try
            {
                var concertsCount = await concertService.ConcertsCount();

                pagesCount = (int)Math.Ceiling((double)concertsCount / AppConstants.PAGE_SIZE);

                ConcertTreshold = 4;
                Concerts.Clear();
                var concerts = await concertService.GetAllConcerts();

                Concerts.AddRange(concerts);
                FilteredConcerts.AddRange(concerts);
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
            }
            finally
            {
                IsBusy = false;
            }
        }