code: public R download(OutputStream out, IOUtil.ProgressListener progressListener)
              throws DbxException,  IOException {
          return download(new ProgressOutputStream(out, progressListener));
      }
docs: This method is the same as {@link #download(OutputStream)} except for allowing to track
  download progress.
  
  @param out {@code OutputStream} to write response body to
  @param progressListener {@code IOUtil.ProgressListener} to track the download progress.
  @return Response from server
  @throws DbxException if an error occurs reading the response or response body.
  @throws IOException if an error occurs writing the response body to the output stream.