setProperties(values, silent) {
    for (const key in values) {
      this.set(key, values[key], silent);
    }
  }
Sets a collection of key-value pairs.  Note that this changes any existing
properties and adds new ones (it does not remove any existing properties).
@param {Object<string, *>} values Values.
@param {boolean} [silent] Update without triggering an event.
@api