code: private void makeImmutable(final AutoBean<? extends BaseProxy> toMutate) {
      // Always diff'ed against itself, producing a no-op
      toMutate.setTag(Constants.PARENT_OBJECT, toMutate);
      // Act with entity-identity semantics
      toMutate.setTag(REQUEST_CONTEXT_STATE, null);
      toMutate.setFrozen(true);
    }
docs: Make an EntityProxy immutable.