code: public static ServiceConfigSupplier create() {
      NetHttpTransport httpTransport = new NetHttpTransport();
      JacksonFactory jsonFactory = new JacksonFactory();
      GoogleCredential credential;
      try {
        credential = GoogleCredential.getApplicationDefault(httpTransport, jsonFactory)
            .createScoped(SCOPES);
      } catch (IOException e) {
        throw new IllegalStateException("could not get credentials for fetching service config!");
      }
      return new ServiceConfigSupplier(
          new SystemEnvironment(), httpTransport, jsonFactory, credential);
    }
docs: Create a {@link ServiceConfigSupplier} instance.
  
  @return a {@code ServiceConfigSuppler}