@Override
  protected void serializeStateData(ProcedureStateSerializer serializer) throws IOException {
    super.serializeStateData(serializer);
    serializer.serialize(EnablePeerStateData.getDefaultInstance());
  }
The procedure for enabling a replication peer.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/replication/EnablePeerProcedure.java