public void preTransitReplicationPeerSyncReplicationState(String peerId,
    SyncReplicationState state) throws IOException {
    execOperation(coprocEnvironments.isEmpty() ? null : new MasterObserverOperation() {
      @Override
      public void call(MasterObserver observer) throws IOException {
        observer.preTransitReplicationPeerSyncReplicationState(this, peerId, state);
      }
    });
  }
Invoked after rollback merge regions operation
@param regionsToMerge the regions to merge
@param user           the user
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java