How to change UISearchController.searchBar.height in iOS11?

Question

navigationBar.frame.size.height is 44.0f;

but UISearchController.searchBar.height is 56.0f;

[self.view addSubview:self.searchController.searchBar];

How to change UISearchController.searchBar.height in iOS11 ? searchBar.frame.size.height = 35 is of no use