[vtkusers] streaming reader

[tom fogal]

Hi all, I'm looking into implementing a VTK reader that supports
streaming. I was looking for additional information on the
implementation of such a reader.

It appears I simply split the data into pieces, but then what?
Specifically I'm wondering:

  - must i segment data in advance of the first 'read' (Execute) of the
      source's output?
  - how does a downstream filter know the data can be streamed?
  - what method[s] must be implemented to read a piece, and (similar to
      above) how do downstream filters know which method that is
      (virtual functions, i imagine?)

The underlying file format is HDF5 based, so I'm hoping I can read
whatever the user currently wants for Extents, and then dynamically
decide how I can split that sub-chunk into vtk pieces.

Any thoughts? Has anyone else implemented an hdf5-based reader?

-tom