trk-io implements a TrackVis (.trk) reader and writer.

Highlights

• Can read and write TrackVis files. Handles affine transformation as nibabel.streamlines and MI-Brain would.
• Reading and writing is tested as much as in nibabel.streamlines.
• Reader can read all streamlines at once or can be used as a generator. Handles endianness.
• Write all at once or streamline per streamline.
• Follows nibabel.streamlines architecture (all 3D points are in a single Vec![Point3D]). Currently, this is only useful for performance, but it may lead to easier changes when and if we support BLAS.