Part of step 3 of olv/venus-protocol#4. This also pulls in an unrelated change to the headers from olv/venus-protocol!60 because it's easier to include here than to coordinate separate MRs landing around the same time.
I'll wait to merge this until step 3 commences.
Venus integrators should be careful to ensure the ordering described in olv/venus-protocol#4 before integrating this change.
Signed-off-by: Ryan Neph email@example.com