Use custom UISearchBar with UISearchController - ios

Question

I want to use a custom UISearchBar with the UISearchController as navigation title to work around the issue with iOS 11 that the height changed from 44 to 56 points. But I fail to understand how I can set the custom search bar to the search controller - the searchbar property is read-only. All my searches on the topic didn't result in anthing that helps me get on the right path.
Here is my search controller code:
Note: AppSearchControllerViewController is a simple UITableViewController displaying the results via an NSMutableArray
Note 2: the view controller implements the delegate "UISearchBarDelegate"
-(void)viewDidLoad {
searchResultsController = [[AppSearchControllerViewController alloc] init];
appSearchController = [[UISearchController alloc] initWithSearchResultsController:searchResultsController];
[searchResultsController setParentNavigationController:self.navigationController];
appSearchController.searchResultsUpdater = self;
appSearchController.dimsBackgroundDuringPresentation = YES;
// Usually one would set up the searchbar like this
// self.navigationItem.titleView = appSearchController.searchBar;
// but instead I do this:
[self addSearchBar];
}
- (void)addSearchBar {
_searchBar = [self addSearchBarWithFrame:CGRectMake(0, 0, kScreenWidth - 2 * 44 - 2 * 15, 44)];
UIView *wrapView = [[UIView alloc] initWithFrame:_searchBar.frame];
[wrapView addSubview:_searchBar];
self.navigationItem.titleView = wrapView;
}
- (WMSearchBar *)addSearchBarWithFrame:(CGRect)frame {
self.definesPresentationContext = YES;
WMSearchBar *searchBar = [[WMSearchBar alloc]initWithFrame:frame];
searchBar.delegate = self;
searchBar.placeholder = [Language get:#"APP_SEARCH_NAVBAR_TEXTFIELD_SEARCH_PLACEHOLDER"];
[searchBar setShowsCancelButton:NO];
[searchBar setTintColor:KGenericColor];
if (self.isChangeSearchBarFrame) {
CGFloat height = searchBar.bounds.size.height;
CGFloat top = (height - 20.0) / 2.0;
CGFloat bottom = top;
searchBar.contentInset = UIEdgeInsetsMake(top, 0, bottom, 0);
}
return searchBar;
}
WMSearchBar class is from this Github repo: https://github.com/DreamTravelingLight/searchBarDemo
This make the search bar perfectly fit again to 44 points and also do the fade in/out animation on controller transitions.
The issue is now, that I receive all the events from the search bar - that all works. But the search results controller is not triggered so the results also don't display.
I tried also to set the original search bar's text from my custom new search bar, but same effect - results controller does not show up. What do I need to do to wire in the new search bar and replace the old one?
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
NSLog(#"textDidChange: %#", searchText);
appSearchController.searchBar.text = searchText;
...