[vtkusers] Why is vtkImageIterator EndOfSlicePointer not available?

[Georg Ziegler]

Hello!
I'm developing an Image Filter that processes each z-slice of a 
vtkImageData differently.
I would like to use vtkImageIterator but it cannot tell me when the end 
of a slice is reached (only end of span).
Only BeginSpan() and EndSpan() are public.

Is there a reason why there is no EndSlice() function?
The class has a protected reference to SliceEndPointer so I guess it 
would be simple to make it available.

I know there is the workaround of counting spans and/or pixels, which I 
have used so far, but it seems cumbersome.

Regards,
Georg