IncludedData example

  protected function resolveIncludeTree(array $include_tree, Data $data, Data $includes = NULL) {
    $includes = is_null($includes) ? new IncludedData([]) : $includes;
    foreach ($include_tree as $field_name => $children) {
      $references = [];
      foreach ($data as $resource_object) {
        // Some objects in the collection may be LabelOnlyResourceObjects or         // EntityAccessDeniedHttpException objects.         assert($resource_object instanceof ResourceIdentifierInterface);
        $public_field_name = $resource_object->getResourceType()->getPublicName($field_name);

        if ($resource_object instanceof LabelOnlyResourceObject) {
          $message = "The current user is not allowed to view this relationship.";
          $exception = new EntityAccessDeniedHttpException($resource_object->getEntity(), AccessResult::forbidden("The user only has authorization for the 'view label' operation."), '', $message, $public_field_name);