* Returns the lookup table entry for stream @stream_idx of the inode, where
* stream_idx = 0 means the default un-named file stream, and stream_idx >= 1
* corresponds to an alternate data stream.
* Returns the lookup table entry for stream @stream_idx of the inode, where
* stream_idx = 0 means the default un-named file stream, and stream_idx >= 1
* corresponds to an alternate data stream.