title: error showing downloadUrl might not have been initialized
body: <pre><code>filepath.putFile(mImageUri).addOnSuccessListener(new OnSuccessListener&lt;UploadTask.TaskSnapshot&gt;() {
              @Override
              public void onSuccess(final UploadTask.TaskSnapshot taskSnapshot) {
                 final   Uri downloadUrl =taskSnapshot.getStorage().getDownloadUrl().addOnSuccessListener(new OnSuccessListener&lt;Uri&gt;() {
                      @Override
                      public void onSuccess(Uri uri) {
  
                          Toast.makeText(getBaseContext(), "Upload success! URL - " + downloadUrl.toString() , Toast.LENGTH_SHORT).show();
  
                      }
                  });
  </code></pre>
  
  <p>this is a snippet of my code,actually there is an error inside onSuccess(Uri uri) method which is in</p>
  
  <blockquote>
    <p><code>downloadUrl.toString()</code></p>
  </blockquote>
  
  <p>and the error is varible <code>downloadUrl</code> might not have been initialized</p>