docs: @Nonnull
    public static ESuccess check (@Nonnull @Nonempty final String sServerSideKey,
                                  @Nullable final String sReCaptchaResponse)
    {
      ValueEnforcer.notEmpty (sServerSideKey, "ServerSideKey");
  
      if (StringHelper.hasNoText (sReCaptchaResponse))
        return ESuccess.SUCCESS;
  
      final HttpClientFactory aHCFactory = new HttpClientFactory ();
      // For proxy etc
      aHCFactory.setUseSystemProperties (true);
  
      try (HttpClientManager aMgr = new HttpClientManager (aHCFactory))
      {
        final HttpPost aPost = new HttpPost (new SimpleURL ("https://www.google.com/recaptcha/api/siteverify").add ("secret",
                                                                                                                    sServerSideKey)
                                                                                                              .add ("response",
                                                                                                                    sReCaptchaResponse)
                                                                                                              .getAsURI ());
        final ResponseHandlerJson aRH = new ResponseHandlerJson ();
        final IJson aJson = aMgr.execute (aPost, aRH);
        if (aJson != null && aJson.isObject ())
        {
          final boolean bSuccess = aJson.getAsObject ().getAsBoolean ("success", false);
  
          if (GlobalDebug.isDebugMode ())
            LOGGER.info ("ReCpatcha Response for '" + sReCaptchaResponse + "': " + aJson.getAsJsonString ());
  
          return ESuccess.valueOf (bSuccess);
        }
      }
      catch (final IOException ex)
      {
        LOGGER.warn ("Error checking ReCaptcha response", ex);
      }
      return ESuccess.FAILURE;
    }