@Override
    public ReplicationPeerConfig build() {
      // It would be nice to validate the configuration, but we have to work with "old" data
      // from ZK which makes it much more difficult.
      return new ReplicationPeerConfig(this);
    }
Use remote wal dir to decide whether a peer is sync replication peer
hbase-client/src/main/java/org/apache/hadoop/hbase/replication/ReplicationPeerConfig.java