How to enable anti-aliasing for a polyline drawn with WPF StreamGeometry?

Question

I need to draw a polyline into a DrawingVisual. I'm using StreamGeometry for performance reasons. The problem I have is that I can't figure out how to enable anti-aliasing. I can't find any method or property on StreamGeometry or on DrawingContext for anti-aliasing control.

The code below is in IronPython, but it shouldn't matter:

geometry = StreamGeometry()
context = geometry.Open()
context.BeginFigure(Point(10, 10), False, False)
context.LineTo(Point(100, 100), True, False)
context.LineTo(Point(200, 300), True, False)
context.Close()

dv = DrawingVisual()
dc = dv.RenderOpen()
dc.DrawGeometry(None, Pen(Brushes.Blue, 1), geometry)
dc.Close()