title: AFNetworking and UIImageView updating threading issues
body: <p>So I have a UITableView with a custom UITableViewCells and inside my custom cell I have a UIImageView in which I use AFNetworking category's to load the image:</p>
  
  <pre><code>NSString *imageURLString = [[object.image_ valueForKey:@"low_resolution"] valueForKey:@"url"];
      NSURLRequest *imageURLRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:imageURLString] cachePolicy:NSURLRequestReturnCacheDataElseLoad timeoutInterval:30];
      [self.imageView_ setImageWithURLRequest:imageURLRequest andAnimate:YES placeholderImage:nil success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image){
  
      }failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error){
          NSLog(@"FAILED");
      }];
  </code></pre>
  
  <p>The issue is that, sometimes when you scroll down.. it seems there's a long delay until the image request is triggered. I am testing in a very good connection. Why is this happening?</p>
  
  <p>I am not sure my self whether the image request is triggered at a later time or the response just gets back at a latter point. But what I am seeing is that initially when the app loads the images loads fine. As I scroll down then all of the images are white.. if I wait patiently enough for like 60 seconds, then it loads up.</p>