title: How use @WorkerThread annotation in android project?
body: <p>Before I used some way for call code in non ui thread (AsyncTask, Loader etc) . But now I try to use @WorkerThread annotation for method, it called some network request</p>
  
  <pre><code>@WorkerThread
      public void downloadInFile(final String url, final String rootDirectory, final OnFinishLoadAudioInFile onFinishLoadAudioInFile,
                                 final OnUpdateLoadAudio onUpdateLoadAudio) {
          final String fileName = URLUtil.guessFileName(url,  null, null);
          downloadFile(url, rootDirectory + File.pathSeparator + fileName, onFinishLoadAudioInFile, onUpdateLoadAudio);
      }
  </code></pre>
  
  <p>, and have <code>android.os.NetworkOnMainThreadException</code>. How use <code>@WorkerThread</code> annotation correctly?</p>