title: NSURLConnection sendAsynchronousRequest with retry functionality
body: <p>I have my main UI thread that calls <code>sendAsynchronousRequest</code> method of <code>NSURLConnection</code> to fetch data.</p>
  
  <pre><code>[NSURLConnection sendAsynchronousRequest:[self request] 
   queue:[NSOperationQueue alloc] init
   completionHandler:
          ^(NSURLResponse *response, NSData *data, NSError *error)       
          {
              if (error)
              {
                 //error handler 
              }
              else 
              {
                 //dispatch_asych to main thread to process data.
              } 
          }];
  </code></pre>
  
  <p>All this is fine and good.</p>
  
  <p>My question here is, I need to implement retry functionality on error.</p>
  
  <ol>
  <li>Can I do it in this block and call <code>sendSynchronousRequest</code> to retry as this is the background queue.</li>
  <li>Or dispatch to main thread and let the main thread handle retry (by calling <code>sendAsynchronousRequest</code> and repeating the same cycle).</li>
  </ol>