Per infinispan-dev list:

Pedro:

Can we remove the ReplicationQueue? First, it does not have any benefit
(JGroups already bundles the message and the Network can do it too) and
second, it is not more efficient (when the message is delivered, we
process the commands sequentially. So, if the first command blocks, the
other commands are not processed until it finished). Third, it is
complex if you have commands with multiple delivers orders (no order,
FIFO, total)

Dan:

+1, the replication queue has the same purpose as the bundler in
JGroups. And while the JGroups bundler has multiple options that keep
evolving, our replication queue still has the same algorithm it had in
4.0.