docs: public AuthRequest login(String emailOrUsername, String password) {
          Asserts.assertNotNull(emailOrUsername, "email or username");
          Asserts.assertNotNull(password, "password");
  
          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, "password");
          request.addParameter(KEY_USERNAME, emailOrUsername);
          request.addParameter(KEY_PASSWORD, password);
          return request;
      }