feature requests: support keep origin ordering of the queryset.

[ramwin]

In most cases, We want to sort a queryset by update_datetime and then iterate it.

e.g. send a message when an new vedio was published or updated.

last_update_datetime = cache.get("last-update-datetime")
for vedio in chunkator(Vedio.objects.filter(update_datetime__gte=last_update_datetime).order_by("update_datetime", 200):
    send_notify(vedio)
    cache.set("last-update-datetime", vedio.update_datetime)