rom `constructor`, `_initializeProperties`),
       * `attributeChangedCallback`, or values propagated from host e.g. via
       * bindings.  `super.ready()` must be called to ensure the data system
       * becomes enabled.
       *
       * @public
       */
      ready() {
        this.__dataReady = true;
        // Run normal flush
        this._flushProperties();
      }

      /**
       * Callback called when any properties with accessors created via
       * `_createPropertyAccessor` have been set.
