code: public HttpURLConnection attribution(String writeKey) throws IOException {
      HttpURLConnection connection =
          openConnection("https://mobile-service.segment.com/v1/attribution");
      connection.setRequestProperty("Authorization", authorizationHeader(writeKey));
      connection.setRequestMethod("POST");
      connection.setDoOutput(true);
      return connection;
    }
docs: Return a {@link HttpURLConnection} that writes gets attribution information from {@code
  https://mobile-service.segment.com/attribution}.