code: public String getDownloadFileUrl(final Path path) {
          final StringBuilder sb = new StringBuilder(GWT.getModuleBaseURL() + EXPORT_SERVLET_URL);
          sb.append("?").append("path").append("=").append(URL.encode(path.toURI()));
          return sb.toString();
      }
docs: <p>Returns the download URL for a given file provided by a servlet method.</p>
  @param path The path of the file.