public function getAll()
    {
        $fields = $this->fields;
        $cacheControlHeader = $this->getCacheControlHeader();
        $fields['Cache-Control'] = [$cacheControlHeader];
        if (empty($cacheControlHeader)) {
            unset($fields['Cache-Control']);
        }
        return $fields;
    }
public function getAll()
    {
        $fields = $this->fields;
        $cacheControlHeader = $this->getCacheControlHeader();
        $fields['Cache-Control'] = [$cacheControlHeader];
        if (empty($cacheControlHeader)) {
            unset($fields['Cache-Control']);
        }
        return $fields;
    }
public function getAll ( ) { $ fields = $ this -> fields ; $ cacheControlHeader = $ this -> getCacheControlHeader ( ) ; $ fields [ 'Cache-Control' ] = [ $ cacheControlHeader ] ; if ( empty ( $ cacheControlHeader ) ) { unset ( $ fields [ 'Cache-Control' ] ) ; } return $ fields ; }
Returns all header fields

Note that even for those header fields which exist only one time, the value is
returned as an array (with a single item).

@return array
@api
Returns all header fields