public static void registerInstantiator() {
    Instantiator.register(new Instantiator(DeltaSessionAttributes.class, 347) {
      @Override
      public DataSerializable newInstance() {
        return new DeltaSessionAttributes();
      }
    });
  }
This class implements synchronous attribute delta propagation. Updates to attributes are
immediately propagated.
extensions/geode-modules-session-internal/src/main/java/org/apache/geode/modules/session/internal/filter/attributes/DeltaSessionAttributes.java