The implementation of supporting adding skb to collections is flaky as Kui-Feng has pointed out in offline discussion. Basically, supporting special BTF fields in unions needs more care. I will defer patch 5-12 to another patchset after the first BPF Qdisc patchset lands. While the performance of qdiscs implemented with the first series will not be as good, this will make the patchset easier to review.
