title: Implementing Progress Indictor For NSURLConnectionDelegate protocol
body: <p>I'm trying to do some progress indication for when trying to upload and download a file.  </p>
  
  <p>Been reading and looks like this is the method that I need to use.</p>
  
  <pre><code>- (void)connection:(NSURLConnection *)connection didSendBodyData:(NSInteger)bytesWritten totalBytesWritten:(NSInteger)totalBytesWritten totalBytesExpectedToWrite:(NSInteger)totalBytesExpectedToWrite
  </code></pre>
  
  <p>I'd like to read more about how that function works (i.e when is it called etc), but can't seem to find the reference documentation. I went to this URL but it does not say anything about that particular function.</p>
  
  <p><a href="https://developer.apple.com/library/mac/#documentation/Foundation/Reference/NSURLConnectionDelegate_Protocol/Reference/Reference.html%23//apple_ref/occ/intf/NSURLConnectionDelegate" rel="nofollow">https://developer.apple.com/library/mac/#documentation/Foundation/Reference/NSURLConnectionDelegate_Protocol/Reference/Reference.html%23//apple_ref/occ/intf/NSURLConnectionDelegate</a></p>
  
  <p>Where can I read more about it?</p>
  
  <p>Thank you,<br>
  Tee</p>