title: Add custom Button with AsyncDisplayKit
body: <p>I am developing an IOS application. I use Facebook AsyncDisplayKit library. I want to a button in ASNodeCell Bu I got "<strong>Variable 'node' is uninitialized when captured by block.</strong> How can I add UIButton or UIWebView control in ASNodeCell. Please help me</p>
  
  <pre><code>dispatch_queue_t _backgroundContentFetchingQueue;
      _backgroundContentFetchingQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0);
  
  dispatch_async(_backgroundContentFetchingQueue, ^{
      ASDisplayNode *node = [[ASDisplayNode alloc] initWithViewBlock:^UIView *{
          UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
          [button sizeToFit];
          node.frame = button.frame;
          return button;
      }];
  
                             // Use `node` as you normally would...
      node.backgroundColor = [UIColor redColor];
  
      [self.view addSubview:node.view];
  });
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/HHygW.png" alt="enter image description here"></p>