docs: public URL signUrlWithSigner(String keyPath) throws IOException {
      // [START signUrlWithSigner]
      URL signedUrl =
          blob.signUrl(
              14,
              TimeUnit.DAYS,
              SignUrlOption.signWith(
                  ServiceAccountCredentials.fromStream(new FileInputStream(keyPath))));
      // [END signUrlWithSigner]
      return signedUrl;
    }