Packs queued before this call are handed to register at once; packs pushed
afterwards go straight through. A second bundle adopting the queue receives
every pack the first already took, and chains onto it for the rest, so two
MAIDR bundles on one page both hear every pack whenever it arrived.
Takes over the pack queue for a registry.
Packs queued before this call are handed to
registerat once; packs pushed afterwards go straight through. A second bundle adopting the queue receives every pack the first already took, and chains onto it for the rest, so two MAIDR bundles on one page both hear every pack whenever it arrived.