title: Can't get allHeaderFields from NSURLConnection.sendSynchronousRequest with swift
body: <p>As the response required for <code>NSURLConnection.sendSynchronousRequest</code> is now requiring <code>NSURLResponse</code> not <code>NSHTTPURLResponse</code> I can't get <code>allHeaderFields</code>.. Is there something I can do here?</p>
  
  <pre><code>var newRequest: NSMutableURLRequest = NSMutableURLRequest(URL: request.URL)
  newRequest.HTTPMethod = "HEAD"
  var response: NSURLResponse
  NSURLConnection.sendSynchronousRequest(newRequest, returningResponse: &amp;response, error: nil)
  if response.respondsToSelector(Selector(allHeaderFields)) {
      let allHeaders = response.allHeaderFields
  }
  </code></pre>
  
  <p>In the old Objective-C version I was doing this which no longer works in swift..</p>
  
  <pre><code>NSMutableURLRequest *newRequest = [NSMutableURLRequest requestWithURL:[request URL]];
  [newRequest setHTTPMethod:@"HEAD"];
  NSHTTPURLResponse *response;
  [NSURLConnection sendSynchronousRequest:newRequest returningResponse:&amp;response error: NULL];
  if ([response respondsToSelector:@selector(allHeaderFields)]) {
      NSDictionary *dictionary = [response allHeaderFields];
  }
  </code></pre>