Give up replicating anything in S state

When we transit the remote S cluster to DA, and then transit the old A cluster to S, it is possible that we still have some entries which have not been replicated yet for the old A cluster, and then the async replication will be blocked.

And this may also lead to data inconsistency after we transit it to DA back later as these entries will be replicated again, but the new data which are replicated from the remote cluster will not be replicated back, which introduce a whole in the replication.