protected function computeCacheControlValue()
{
if (!$this->cacheControl && !$this->has('ETag') && !$this->has('Last-Modified') && !$this->has('Expires')) {
protected function computeCacheControlValue()
{
if (!$this->cacheControl && !$this->has('ETag') && !$this->has('Last-Modified') && !$this->has('Expires')) {