@Override
  public AttributesMutator getAttributesMutator() {
    throw new UnsupportedOperationException();
  }
A wrapper class over an actual Region instance. This is used when the multiuser-authentication
attribute is set to true.

@see ProxyCache
@since GemFire 6.5
geode-core/src/main/java/org/apache/geode/cache/client/internal/ProxyRegion.java