Looking for a way to draw "reference" lines on a chart - in this case the reference line is a diagonal line showing the 1:1 representation of X:Y.  In many ways this is like a const line except that the value is not constant along a single axis but rather a constant formula (i.e. X/Y = 1).

I have currently simply added a single NLineSeries to the chart but was looking for a more elegant way to do this without all the clutter of dealing with a series in the data that isn't really a series (i.e. all kinds of code in my custom tools to detect and filter out the const line series)