public override void WillDisplayNodeForRowAtIndexPath(ASTableView tableView, NSIndexPath indexPath)
            {
                if (_source == null)
                {
                    var table = tableView as ASTableView;
                    _source = table.TableNode.DataSource as GroupedTableDataSource <DateTimeOffset, ChatMessageViewModel>;
                }

                var count = _source.DataSource[0].Count;

                if (indexPath.Section == _source.DataSource.Count - 1 && indexPath.Row == count - 1)
                {
                    LastItemRequested?.Invoke(this, EventArgs.Empty);
                }
            }
 public override void WillDisplayNode(ASTableView tableView, ASCellNode node, NSIndexPath indexPath)
 {
     WillDisplayCell?.Invoke(indexPath.Section, indexPath.Row);
 }