if the partialobject loop does not make progress (xlen = 0), leave it
if the partialobject loop does not make progress (xlen = 0), leave it

https://github.com/gphoto/libgphoto2/issues/487

gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2