private function parseDirectives($header)
    {
        $directives = [];

        foreach (explode(';', $header) as $directive) {
            $parts = explode(' ', trim($directive));
            if (\count($parts) < 1) {
                continue;
            }
            $name = array_shift($parts);
            $directives[$name] = $parts;
        }

        return $directives;
    }