Hello everyone!
I have two questions of the community. The first is whether work on this would be accepted by the Swift project, as we wouldn't want to expend efforts on something we'd have to carry as our own patches to upstream. The second is if there is any interest from other people to collaborate on design/implementation of the locking feature.
Happy to take replies off-list if people prefer, and thanks for reading this far!
(Ob-reply: Yes, we know Ceph RGW does this already. We use Swift for Object for $REASONS, which we'd like to keep doing.)