title: DownloadManager doesn't start to download file
body: <p>Imagine that i want to download this file (random file):
  <a href="http://www.analysis.im/uploads/seminar/pdf-sample.pdf" rel="noreferrer">http://www.analysis.im/uploads/seminar/pdf-sample.pdf</a></p>
  
  <p>This is my code:</p>
  
  <pre><code>DownloadManager.Request req = new DownloadManager.Request(Uri.parse("http://www.analysis.im/uploads/seminar/pdf-sample.pdf"));
  
  req.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE)
     .setAllowedOverRoaming(false)
     .setTitle("Random title")
     .setDescription("Random description")
     .setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "pdf-sample.pdf");
  </code></pre>
  
  <p>In debug mode i can see that all parameters are corrects so why the download doesn't start?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>My current permissions:</p>
  
  <pre><code>&lt;uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/&gt;
  &lt;uses-permission android:name="android.permission.INTERNET"/&gt;
  </code></pre>