How to load more items when scroll reached the end of list?

<syncfusion:SfListView x:Name="listView" ItemsSource="{Binding ContactsInfo}" ItemSize="60">
  <syncfusion:SfListView.FooterTemplate>
    <DataTemplate>
      <Grid>
        <ActivityIndicator x:Name="activityIndicator" Color="Blue" IsRunning="True"/>
      </Grid>
    </DataTemplate>
  </syncfusion:SfListView.FooterTemplate>
<syncfusion:SfListView.ItemTemplate>
  <DataTemplate>
    <ViewCell>
      <ViewCell.View>
        <Grid>
          <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="1" />
          </Grid.RowDefinitions>
          <Grid>
            <Grid.ColumnDefinitions>
              <ColumnDefinition Width="50" />
              <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>
             <Image Source="{Binding ContactImage}" HeightRequest="50"/>
             <Grid Grid.Column="1">
               <Grid.RowDefinitions>
                 <RowDefinition Height="*" />
                 <RowDefinition Height="*" />
               </Grid.RowDefinitions>
               <Label Text="{Binding ContactName}"/>
               <Label Grid.Row="1" Grid.Column="0" Text="{Binding ContactNumber}" />
              </Grid>
            </Grid>
           <StackLayout Grid.Row="1" BackgroundColor="Gray" HeightRequest="1"/>
        </Grid>
       </ViewCell.View>
     </ViewCell>
   </DataTemplate>
 </syncfusion:SfListView.ItemTemplate>
</syncfusion:SfListView>

public class ContactsViewModel: INotifyPropertyChanged
{
  bool isBusy = false;
  private int Id = 1;
 
  public ContactsViewModel ()
  {
    contactsinfo = new ObservableCollection<Contacts> ();
    LoadMoreData();
  }
 
  public async void LoadMoreData ()
  {
    isBusy = false;
 
    //To show ActivityIndicator if the items are loaded in the view. 
    if (contactsinfo.Count > 0)
      await Task.Delay(3000);
 
    //To ignore if items are being added till delayed time.
    if (isBusy)
      return;
 
    for (int i = 0; i < 20; i++)
    {
      Random r = new Random ();
      var contact = new Contacts ();
      contact.UserId = Id++;
      contact.ContactName = CustomerNames[i];
      contact.ContactNumber = 130+Id + " - " + 390+Id;
      contact.ContactImage = ImageSource.FromResource("SfListViewSample.Images.Image" + i + ".png");
      contactsinfo.Add(contact);
   }
    isBusy = true;
  }
}

public partial class MainPage : ContentPage
{
  private ContactsViewModel viewModel;
  ScrollAxisBase scrollRows;
  public bool isFooterLoaded;
  VisualContainer visualContainer;
 
  public MainPage()
  {
  InitializeComponent();
   viewModel = new ContactsViewModel();
   this.BindingContext = viewModel;
   listView.FooterSize = 40;
  visualContainer = listView.GetType().GetRuntimeProperties().First(p => p.Name == "VisualContainer").GetValue(listView) as VisualContainer;
  scrollRows = visualContainer.GetType().GetRuntimeProperties().First(p => p.Name == "ScrollRows").GetValue(visualContainer) as ScrollAxisBase;
   scrollRows.Changed += ScrollRows_Changed;
  }
 
  private void ScrollRows_Changed(object sender, ScrollChangedEventArgs e)
  {
    var lastIndex = scrollRows.LastBodyVisibleLineIndex;
    var header = (listView.HeaderTemplate != null && !listView.IsStickyHeader) ? 1 : 0;
    var footer = (listView.FooterTemplate != null && !listView.IsStickyFooter) ? 1 : 0;
    var displayItemsCount = listView.DataSource.DisplayItems.Count;
    var totalItems = displayItemsCount + header + footer;
 
    //To stop loading when 60 items added to display items.
    if (displayItemsCount >=60)
    {
      listView.FooterSize = 0;
        return;
    }
 
      if (totalItems > 0 && lastIndex == (totalItems - 1))
      {
        if (!isFooterLoaded)
        {
          viewModel.LoadMoreData();
          isFooterLoaded = true;
        }
      }
      else
        {
          isFooterLoaded = false;
        }
     }
   }
}