protected function renderToggleButton()
    {
        $icon = $this->htmlHlp->tag('span', '', ['class' => 'navbar-toggler-icon']);
        $screenReader = isset($this->screenReaderToggleText)
            ? "<span class=\"sr-only\">{$this->screenReaderToggleText}</span>"
            : '';

        return $this->htmlHlp->button("{$screenReader}\n{$icon}", [
            'class' => 'navbar-toggler',
            'data-toggle' => 'collapse',
            'data-target' => "#{$this->containerOptions['id']}",
        ]);
    }