Right, I added #237!

Added  #236

there could also be an `ILabelProvider` interface to improve performance (avoid the reflection)

See the `LineSeries.LabelFormatString`. I think you can set it to "{Label}", where "Label" is the name of the property in your AnnotatedDataPoint that contains the labels. This is using the extended string formatting syntax (that I hope works, otherwise it is an easy fix!)

ps. It would be great to have this added as an example in the example library!

I see two possible solutions:
1. use TextAnnotations for the H,Z and T labels
2. use the labelling feature for the LineSeries. Create a new point type that also includes a property that returns "H","Z","T" or null. Bind the points to the ItemsSource on the LineSeries, and set the format string for the labels to use the property just mentioned. I am not sure if this works right now, but it should be easy to fix!

There is also an `ActualPoints` property that I recommend to use!

The `FontSize` property should be used. If it is not set, the `FontSize` of the parent `PlotModel` should be used. 
If it is not working, please add an issue at GitHub!

Sorry, text wrapping is not supported (yet). Please add this in the GitHub issues! Remember to include a small example that reproduces the problem :-)
It should not be difficult to implement for rectangles, but I see some challenges if you want this for polygons....

The StairStep series has not been profiled for such big datasets yet. Can it be solved in a similar way as we do in `LineSeries`? Please create an issue at GitHub and create a small example that shows the problem!

This sounds like a bug. Please add it to the issues at GitHub! Include some simple code that reproduces the error!