title: Downloading large files with AFNetworking
body: <p>I'm trying to implement downloading of a large file and show to user current progress, but block in:</p>
  
  <pre><code>-[AFURLConnectionOperation setDownloadProgressBlock:] 
  </code></pre>
  
  <p>returns incorrect <code>bytesRead</code> and <code>totalBytesRead</code> values (they are smaller than they should be).<br /></p>
  
  <p>For example: If I have a 90MB file and when it downloads completely, latest block invocation in <code>setDownloadProgressBlock:</code> gives me <code>totalBytesRead</code> value about 30MB. On other side, if file is 2MB large, latest block invocation gives correct <code>totalBytesRead</code> 2MB value.</p>
  
  <p>AFNetworking is updated to the latest version from github.<br />
  If AFNetworking can't do it correctly, what solution can I use?</p>
  
  <p><strong>Edit:</strong> I've determined that even if file is not downloaded completely (and this happens every time with relatively big file) AFNetworking calls success block in:</p>
  
  <pre><code>-[AFHTTPRequestOperation setCompletionBlockWithSuccess:failure:]
  </code></pre>
  
  <p>I asked a similar question <a href="https://stackoverflow.com/questions/12722436/afimagerequestoperation-returns-image-that-not-downloaded-competely">here</a> about this situation, but didn't get any answers.<br />
  I can check in code downloaded and real file sizes, but <code>AFNetworking</code> has no API for continuation of partial download.</p>