title: Is addsubview on iOS thread safe?
body: <p>I'm using Apple's <a href="http://developer.apple.com/library/ios/#samplecode/PageControl/Listings/Classes_iPhone_PhoneContentController_m.html" rel="nofollow"> Page Control</a> sample and my UIScrollview isn't smooth when scrolling. I'm thinking about using GCD. I believe that all my code is thread safe, except for my last line which is [self.scrollView addSubview:myView].</p>
  
  <p>The docs that I read all mentions that UIKit is not thread safe, but the examples given are always related to setting values such as self.myLabel.text = @"some text".</p>
  
  <p>Is addSubview thread safe?</p>