$getProperty method
Get a property by identifier on this instance
Implementation
@override
$Value? $getProperty(Runtime runtime, String identifier) {
  try {
    return super.$getProperty(runtime, identifier);
  } on UnimplementedError {
    return $Object(this).$getProperty(runtime, identifier);
  } on EvalUnknownPropertyException {
    return $Object(this).$getProperty(runtime, identifier);
  }
}