title: Dispatch sizeToFit to background
body: <p>How to dispatch to background thread something from this code</p>
  
  <pre><code>-(void)viewDidLayoutSubviews
  {
      [super viewDidLayoutSubviews];
      [self adjustTextToScreen];
  }
  
  -(void)adjustTextToScreen
  {
      //label
      [self.detailedCommonLabel sizeToFit];
      //tableV
      CGRect frame = self.detailedCommonTableV.frame;
      frame.size.height = self.detailedCommonTableV.contentSize.height;
      self.detailedCommonTableV.frame = frame;
      self.tableViewHeight.constant = self.detailedCommonTableV.frame.size.height;
      //back scroll height
      [self.detailedCommonScrollV setContentSize:CGSizeMake(self.detailedCommonScrollV.contentSize.width, self.detailedCommonImageSlider.frame.size.height + self.detailedCommonLabel.frame.size.height + self.detailedCommonTableV.frame.size.height + 40)];
  }
  </code></pre>
  
  <p>properly, because it takes too long for calculating?</p>
  
  <p>I tried different combinations but the didn't work. <code>sizeToFit</code> throws an exception that it must be in main thread. Realm throws some exceptions too.  </p>