public static function encode($value, $ignore = null)
    {
        if (null === $ignore) {
            $ignore = static::CHAR_UNRESERVED
                    . static::CHAR_GEN_DELIMS
                    . static::CHAR_SUB_DELIMS;
        }
        $rawurlencode = function (array $matches) {
            return rawurlencode($matches[0]);
        };

        return preg_replace_callback(
            '/(?:[^' . $ignore . '%]+|%(?![A-Fa-f0-9]{2}))/',
            $rawurlencode,
            $value
        );
    }