title: Get remote file size via HTTP without downloading said file
body: <p>Any way to get the size of a (remote, http) file without actually downloading it?</p>
  
  <p>All other similar questions seem to revolve around grabbing the <code>expectedContentLength</code> from the <code>NSURLResponse</code> object in <code>didReceiveResponse:</code> but I don't want to download the file, I just want to know how big it is. </p>