@RestrictedApi(explanation = "Should only be called in tests", link = "",
      allowedOnPath = ".*/src/test/.*")
  public ReplicationPeerStorage getPeerStorage() {
    return peerStorage;
  }
Set a namespace in the peer config means that all tables in this namespace will be replicated
to the peer cluster.
<ol>
<li>If peer config already has a namespace, then not allow set any table of this namespace to
the peer config.</li>
<li>If peer config already has a table, then not allow set this table's namespace to the peer
config.</li>
</ol>
<p>
Set a exclude namespace in the peer config means that all tables in this namespace can't be
replicated to the peer cluster.
<ol>
<li>If peer config already has a exclude namespace, then not allow set any exclude table of
this namespace to the peer config.</li>
<li>If peer config already has a exclude table, then not allow set this table's namespace as a
exclude namespace.</li>
</ol>
hbase-server/src/main/java/org/apache/hadoop/hbase/master/replication/ReplicationPeerManager.java