protected function _cookies()
{
$cookies = $this->cookies;
$invalid = str_split(",; \\+\t\r\n\v\f");
$replace = array_map('rawurlencode', $invalid);
foreach ($cookies as $key => &$value) {
if (!is_scalar($value)) {
$message = "Non-scalar value cannot be rendered for cookie `{$key}`";
throw new UnexpectedValueException($message);
}
$value = strtr($value, array_combine($invalid, $replace));
$value = "{$key}={$value}";
}
return implode('; ', $cookies);
}