docs: public AuthRequest exchangeCode(String code, String redirectUri) {
          Asserts.assertNotNull(code, "code");
          Asserts.assertNotNull(redirectUri, "redirect uri");
  
          String url = baseUrl
                  .newBuilder()
                  .addPathSegment(PATH_OAUTH)
                  .addPathSegment(PATH_TOKEN)
                  .build()
                  .toString();
          TokenRequest request = new TokenRequest(client, url);
          request.addParameter(KEY_CLIENT_ID, clientId);
          request.addParameter(KEY_CLIENT_SECRET, clientSecret);
          request.addParameter(KEY_GRANT_TYPE, "authorization_code");
          request.addParameter("code", code);
          request.addParameter("redirect_uri", redirectUri);
          return request;
      }