vlib_refcount_add(&lbm->as_refcount, thread_index, b->value[i], -1);
vlib_refcount_add(&lbm->as_refcount, thread_index, 0, 1);
b->vip[i] = ~0;
vlib_refcount_add(&lbm->as_refcount, thread_index, b->value[i], -1);
vlib_refcount_add(&lbm->as_refcount, thread_index, 0, 1);
b->vip[i] = ~0;