protected function parseNestedKeyPairHeader($nestedPairs)
    {
        return array_reduce(explode(';', $nestedPairs), function($result, $pair) {
            $keyVal = explode('=', $pair, 2);
            $key = trim(array_shift($keyVal));
            $val = trim(implode('=', $keyVal));
            if ($key !== '' && $val !== '') {
                $result[$key] = $val;
            }
            return $result;
        }, []);
    }