title: Web page of WKWebView not displaying page inside of dispatch_get_main_queue
body: <p>I'm trying to create multiple WKWebView views inside of a background process and then add them to a view on the main thread once they are all done loading.</p>
  
  <p>Each of the WKWebView's contains a chart rendered via javascript so the load time takes about a second per WKWebView so I'm trying to offload the processing to the background so the UI isn't blocked.</p>
  
  <p>This works fine when dispatch_get_main_queue is commented out, however the ui is blocked for 5-10 seconds.  Only the brown background of the WKWebView shows up, none of the contents from the webpage.</p>
  
  <pre><code> var webViews : [WKWebView] = []   
  
   var myQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
   dispatch_async(myQueue, {
  
   for i in 0...10
   {
        var url : NSURL? = NSURL(string:"http://google.com")
        var req = NSURLRequest(URL:url!)
  
        var webview = WKWebView(frame:CGRectMake(0, height * CGFloat(i), width, height))         
        webview.loadRequest(req)
        webview.backgroundColor = UIColor.brownColor()
  
        self.webViews.append(webview)
    }
  
      dispatch_async(dispatch_get_main_queue(),{
  
        for item in self.webViews
        {
           self.view.addSubview(item)
        }
  
       });
    });
  </code></pre>