anchor.diff:                  public void streamingFailed(StreamingErrorEvent event) {
                       Notification.show("Stream failed, fileName="
                           + event.getFileName());
  +                }
  +
  +                @Override
  +                public boolean isInterrupted() {
  +                    return false;
                   }
               });
           }
  
positive.code: Label dropArea = new Label("Drop files here");
  FileDropTarget<Label> dropTarget = new FileDropTarget<>(dropArea, event -> {
  
      List<Html5File> files = event.getFiles();
      files.forEach(file -> {
          // Max 1 MB files are uploaded
          if (file.getFileSize() <= 1024 * 1024) {
  
negative.code:                 // Output stream to write the file to
                  @Override
                  public OutputStream getOutputStream() {
                      try{
                          return new FileOutputStream("/path/to/files/"
                            + file.getFileName());
                          }catch (FileNotFoundException e) {
                                  e.printStackTrace();
                              }
                      return null;
                  }
  
                  // Returns whether onProgress() is called during upload
  