如何使用LiveCharts更改DataLabels颜色

PieChart pieChart = new PieChart();
pieChart.Series = new SeriesCollection
{
    new PieSeries
    {
        Title = "Series 1",
        Values = new ChartValues<double> { 10, 20, 30, 40 },
        DataLabels = true
    }
};

PieSeries pieSeries = new PieSeries
{
    Title = "Series 1",
    Values = new ChartValues<double> { 10, 20, 30, 40 },
    DataLabels = true
};

// 设置DataLabels的颜色为红色
pieSeries.LabelPoint = point => string.Format("{0} ({1:P})", point.Y, point.Participation);
pieSeries.LabelPoint.Fill = Brushes.Red;

pieChart.Series = new SeriesCollection { pieSeries };