code: public R fetch(String path, String properties, FetchConfig fetchConfig) {
      query.fetch(path, properties, fetchConfig);
      return root;
    }
docs: Additionally specify a FetchConfig to use a separate query or lazy loading
  to load this path.
  <p>
  <pre>{@code
  
  // fetch customers (their id, name and status)
  List<Customer> customers =
  new QCustomer()
  .select("name, status")
  .fetch("contacts", "firstName,lastName,email", new FetchConfig().lazy(10))
  .findList();
  
  }</pre>