public LineChartViewModel()
{
DataSeriesCollection = new ObservableCollection<DataSeries>();
DataSeriesCollection.Added.SubscribeUnmanaged(SeriesAdded);
seriesRemovedSubscription = DataSeriesCollection.Removed.SubscribeUnmanaged(SeriesRemoved);
focusedDataPointSubscription = SubscribeUnmanaged(nameof(FocusedDataSeriesIndex), FocusedSeriesChanged);
focusedDataPointSubscription = SubscribeUnmanaged(nameof(FocusedDataPointIndex), FocusedDataPointChanged);
}