PDF Mosaic: How to add polyline annotation to PDF documents

PDFDocument pdf = new PDFDocument();
pdf.Pages.Add(new PDFPage(PDFPaperFormat.A4));
PDFPointsArray points = new PDFPointsArray();
points.AddPoint(new Point(150, 275));
points.AddPoint(new Point(250, 150));
points.AddPoint(new Point(350, 275));
points.AddPoint(new Point(125, 200));
points.AddPoint(new Point(375, 200));
points.AddPoint(new Point(150, 275));
PDFPolylineAnnotation annot = new PDFPolylineAnnotation(points);
annot.Contents = "Polyline annotations...";
 
pdf.Pages[0].Annotations.Add(annot);
pdf.Save("TestPolylineAnnotation.pdf", true);