Features Suggestion

Currently, if one wants to get the bitmap to a legend with e.g

var legend = FormsPlot.Plot.Legend();
var picture = legend.GetBitmap();

This call returns an error if no plot has a label.
However, there is no way to actually know the number of items in the legend as this property is private.

One could think of two solutions :

• Either not return an error in case the legend is empty but return a null or an equivalent
• Or make the LegendItems list public so that one can check its length prior GetLegendBitmap()

Side note : Wouldn't it be relevant to switch from an LegendItem[] array to a List<LegendItem> as there is intrinsically variable amount of plots in a ScottPlot ?