on the generated class should be called to forward host
       *   properties into the template to prevent unnecessary property-changed
       *   notifications. Any properties referenced in the template that are not
       *   defined in `instanceProps` will be notified up to the template's host
       *   automatically.
       * - `instanceProps`: Dictionary of property names that will be added
       *   to the instance by the templatize owner.  These properties shadow any
       *   host properties, and