title: Is there a way to remove the delay when [NSURLSessionConfiguration backgroundSessionConfiguration] is used?
body: <p>I am trying to run a background NSURLSessionDownloadTask. However, I noticed that it takes approximately 30 seconds before the task actually begins. When I use the defaultSessionConfiguration, the task starts almost immediately. Is there a way to trigger the NSURLSessionDownloadTask immediately when using the backgroundSessionConfiguration? </p>
  
  <p>Below is the result I get when I use backgroundSessionConfiguration:</p>
  
  <pre><code>NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration backgroundSessionConfiguration:[NSString stringWithFormat:bgIdentifier, self.urlModel.code]];
  </code></pre>
  
  <p>Here are the log output. Note that “Start uploading…” is logged right before calling the “resume” method and “Upload progress” is logged in the NSURLSessionTaskDelegate’s didSendData method.</p>
  
  <pre><code>2014-02-18 20:13:55.403 myapp[396:60b] [DoneViewController] Start uploading...
  2014-02-18 20:14:17.699 myapp[396:60b] [DoneViewController] Upload progress - 1%
  2014-02-18 20:14:17.704 myapp[396:60b] [DoneViewController] Upload progress - 2%
  2014-02-18 20:14:17.705 myapp[396:60b] [DoneViewController] Upload progress - 3%
  2014-02-18 20:14:17.706 myapp[396:60b] [DoneViewController] Upload progress - 4%
  </code></pre>
  
  <p>Just for reference, the same thing but with the default session configuration.</p>
  
  <pre><code>NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
  </code></pre>
  
  <p>You can see there is no delay on console result is like this:</p>
  
  <pre><code>2014-02-18 19:57:00.552 myapp[376:60b] [DoneViewController] Start uploading...
  2014-02-18 19:57:00.707 myapp[376:60b] [DoneViewController] Upload progress - 2%
  2014-02-18 19:57:00.710 myapp[376:60b] [DoneViewController] Upload progress - 5%
  2014-02-18 19:57:00.711 myapp[376:60b] [DoneViewController] Upload progress - 8%
  2014-02-18 19:57:00.711 myapp[376:60b] [DoneViewController] Upload progress - 11%
  </code></pre>
  
  <p>Edit: With iOS 7.1, there are times when there are no delays. However, there are still times where there are about 20 second delays.</p>