final String encoded = cookie.getValue();
                            final byte[] compressed = Base64.getUrlDecoder().decode(encoded);
                            final byte[] jsonBytes = gzipDecompress(compressed);
                            final List<?> list = mapper.readValue(jsonBytes, List.class);

                            final List<RequestParameter> result = new ArrayList<>();

        byte[] originalBytes = testData.getBytes();

        byte[] compressed = searchHelper.gzipCompress(originalBytes);
        byte[] decompressed = searchHelper.gzipDecompress(compressed);

        assertEquals(testData, new String(decompressed));
        // For small strings, gzip overhead might make compressed data larger

    result.zstdCompress().buffer().use {
      it.write(this@zstdCompress)
    }
    return result.readByteString()
  }

  private fun ByteString.gzipCompress(): ByteString {
    val result = Buffer()
    (result as Sink).gzip().buffer().use {
      it.write(this@gzipCompress)
    }
    return result.readByteString()
  }

  private fun response(
    url: String,
    body: ByteString,

            assertNotNull(response.getContentAsString());
        }
    }

    // --- GZIP response tests ---

    /**
     * Helper to GZIP-compress a string.
     */
    private byte[] gzipCompress(String text) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try (GZIPOutputStream gos = new GZIPOutputStream(baos)) {
            gos.write(text.getBytes(StandardCharsets.UTF_8));