[vtkusers] vtkImageSkeleton2D code question

[Lauren O'Donnell]

Does anyone know why in vtkImageSkeleton2D ThreadedExecute makes a
temporary copy of the input data to send to vtkImageSkeleton2DExecute?

This seems unnecessary to me since the superclass (vtkImageIterateFilter)
gives the right input and output to Execute each time.

I am just trying to understand this class to see how to write a
vtkImageIterateFilter, so any clarification is appreciated!

Lauren