title: NSURLConnection to upload file asynchonrously?
body: <p>I'm kinda of new at ios development,
  I've been reading and searching but cannot find a working example or an example of
  how to upload a file from iphone to webserver asychronously..</p>
  
  <p>I'm able to upload synchronously using </p>
  
  <pre><code>[NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
  </code></pre>
  
  <p>it works, but it blocks my main thread.</p>
  
  <p>NSUrlConnection has this delegate <code>(connection:didSendBodyData:totalBytesWritten:totalBytesExpectedToWrite:)</code></p>
  
  <p>but I've no idea how to implement it.</p>
  
  <p>Can someone please point me in the right direction?</p>