public Map<String, String> getAdditionalUrlParameters(
      DataVertical dataType, AuthMode mode, OAuth1Step step) {

    if (dataType.equals(PHOTOS) && step == OAuth1Step.REQUEST_TOKEN) {
      return (mode == AuthMode.EXPORT)
          ? ImmutableMap.of(X_AUTH_ACCESS_TYPE, "read")
          : ImmutableMap.of(X_AUTH_ACCESS_TYPE, "write");
    }

    // default
    return Collections.emptyMap();
  }
Class that supplies Twitter-specific OAuth1 info
See https://developer.twitter.com/en/docs/basics/authentication/overview/3-legged-oauth
and https://developer.twitter.com/en/docs/basics/authentication/api-reference
extensions/auth/portability-auth-twitter/src/main/java/org/datatransferproject/auth/twitter/TwitterOAuthConfig.java