Issue #3437286 by immaculatexavier, longwave: Use argument unpacking in...

   *

   * @param string $method

   *   The name of the method to be invoked.

   * @param mixed ...$args

   *   Any arguments to be forwarded to the invoked method.

   *

   * @return array

   *   An array of results keyed by delta.

   */

  protected function delegateMethod($method) {

    $result = [];

    $args = array_slice(func_get_args(), 1);

    foreach ($this->list as $delta => $item) {

      // call_user_func_array() is way slower than a direct call so we avoid

      // using it if have no parameters.

      $result[$delta] = $args ? call_user_func_array([$item, $method], $args) : $item->{$method}();

    }

    return $result;

  protected function delegateMethod($method, ...$args) {

    return array_map(fn($item) => $item->{$method}(...$args), $this->list);

  }

  /**