/**
  * Constructs a FilesUpload__1_0 object.
  *
  * @param array $configuration
  *   A configuration array containing information about the plugin instance.
  * @param string $plugin_id
  *   The plugin_id for the plugin instance.
  * @param mixed $plugin_definition
  *   The plugin implementation definition.
  */
 public function __construct(array $configuration, $plugin_id, $plugin_definition)
 {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     // Set dynamic options that cannot be set in the annotation.
     $plugin_definition = $this->getPluginDefinition();
     $plugin_definition['authenticationOptional'] = (bool) variable_get('restful_file_upload_allow_anonymous_user', FALSE);
     // Store the plugin definition.
     $this->pluginDefinition = $plugin_definition;
 }