UISearchController搜索条动画第一次非常慢

In iOS 9 I am using UISearchController and displaying its search bar within a UIViewController, I am experiencing a lot of lag the first time I click on the search bar and have tried everything i can think of to no avail...below is my code along with a link to a video of the lag happening - the lag happens on both the simulator and my device.In iOS 9 I am using UISearchController and disp