title: Navigation bar gets adjusted after calling completeTransition: in custom transition
body: <p>My goal is to provide zooming modal transition from for the user from a view similar as springboard icons zoom in when launching apps.</p>
  
  <p>The presented view controller zooms in correctly, but the navigation bar has wrong position under the status bar. This position gets corrected after calling [transitionContext completeTransition:finished];. How can I make it correct from the beginning of the transition?</p>
  
  <p>This is a screen recording of the bug: <a href="http://youtu.be/7LKU4lzb-uw">http://youtu.be/7LKU4lzb-uw</a> (the glitch is in the 6th second of the recording)</p>
  
  <p>The UIViewControllerAnimatedTransitioning code:</p>
  
  <pre><code>- (void)animateTransition:(id&lt;UIViewControllerContextTransitioning&gt;)transitionContext
  {
      UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
      UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
      UIView *container = [transitionContext containerView];
  
      CGPoint viewCenter = self.view.center;
      CGSize viewSize = self.view.frame.size;
      CGSize controllerSize = toViewController.view.frame.size;
  
      CGFloat controllerFromX = viewCenter.x - (controllerSize.width / 2);
      CGFloat controllerFromY = viewCenter.y - (controllerSize.height / 2);
  
      CGAffineTransform transform = CGAffineTransformMakeTranslation(controllerFromX, controllerFromY);
      transform = CGAffineTransformScale(transform, viewSize.width / controllerSize.width, viewSize.height / controllerSize.height);
  
      if (self.reverse) {
          [container insertSubview:toViewController.view belowSubview:fromViewController.view];
      } else {
          toViewController.view.transform = transform;
          [container addSubview:toViewController.view];
      }
  
      [UIView animateKeyframesWithDuration:ZoomTransitioningDuration 
                                     delay:0 
                                   options:0 
                                animations:^{
                  if (self.reverse) {
                      fromViewController.view.alpha = 0.0f;
                      fromViewController.view.transform = transform;
                  } else {
                      toViewController.view.transform = CGAffineTransformIdentity;
                  }
          } 
                                completion:^(BOOL finished) {
                  [transitionContext completeTransition:finished];
          }];
  }
  </code></pre>