code: public void addFile(String path, File file, String contentType) throws IOException {
      try (InputStream is = new FileInputStream(file)) {
        addFile(path, is, contentType);
      }
    }
docs: Adds a binary file with explicit mime type.
  @param path Full content path and file name of file
  @param file File with binary data
  @param contentType Mime type, optionally with ";charset=XYZ" extension
  @throws IOException I/O exception