speed up stripwise read as well
speed up stripwise read as well

leiyangyou/libvips,lovell/libvips,mcanthony/libvips,wishabi/libvips,jcupitt/libvips,wishabi/libvips,mcanthony/libvips,lovell/libvips,lovell/libvips,wishabi/libvips,lovell/libvips,jcupitt/libvips,mcanthony/libvips,leiyangyou/libvips,mcanthony/libvips,leiyangyou/libvips,wishabi/libvips,jcupitt/libvips,leiyangyou/libvips,jcupitt/libvips