@param fn Input BAM/CRAM/etc filename
@param fnidx Output filename, or NULL to add .bai/.csi/etc to @a fn
@param min_shift Positive to generate CSI, or 0 to generate BAI
@return 0 if successful, or negative if an error occurred (see
sam_index_build for error codes)
@param fn Input BAM/CRAM/etc filename @param fnidx Output filename, or NULL to add .bai/.csi/etc to @a fn @param min_shift Positive to generate CSI, or 0 to generate BAI @return 0 if successful, or negative if an error occurred (see sam_index_build for error codes)