docs: public Future<OAuth1AccessToken> getAccessTokenAsync(OAuth1RequestToken requestToken, String oauthVerifier,
              OAuthAsyncRequestCallback<OAuth1AccessToken> callback) {
          log("async obtaining access token from %s", api.getAccessTokenEndpoint());
          final OAuthRequest request = prepareAccessTokenRequest(requestToken, oauthVerifier);
          return execute(request, callback, new OAuthRequest.ResponseConverter<OAuth1AccessToken>() {
              @Override
              public OAuth1AccessToken convert(Response response) throws IOException {
                  return getApi().getAccessTokenExtractor().extract(response);
              }
          });
      }