private synchronized void initializeRegistry(boolean client) {
    if (delegate != null) {
      return;
    }
    final TypeRegistration delegateTmp = createTypeRegistration(client);
    delegateTmp.initialize();
    delegate = delegateTmp;
  }
Actually initialize the delegate. This is method is called when the type registry is used. At
that time, it creates the registry.
geode-core/src/main/java/org/apache/geode/pdx/internal/LonerTypeRegistration.java