According to https://developers.google.com/mobile-ads-sdk/docs/admob/ios/quick-start I add AdMob banner to my View Controller with code
self.bannerView.adUnitID = @"ID_GOES_HERE";
self.bannerView.rootViewController = self;
[self.bannerView loadRequest:[GADRequest request]];
what actually works well, however every time I need to wait 1/2 seconds until banner appears. Can I for example initialize somehow all banners which I want to use in my app in AppDelegate, loading screen or somewhere else, save them in sharedManager and then just to display in View Controllers without delay, at the same time as other elements of UI?