code: public static function set($name, $value, $expiration = null) {
          if ($expiration === null) {
              // Use the default expiration
              $expiration = static::$expiration;
          }
  
          if ($expiration !== 0) {
              // The expiration is expected to be a UNIX timestamp
              $expiration += time();
          }
  
          // Add the salt to the cookie value
          $value = static::salt($name, $value) . '~' . $value;
  
          return setcookie($name, $value, $expiration, static::$path, static::$domain, static::$secure, static::$httponly);
      }
docs: Sets a signed cookie. Note that all cookie values must be strings and no
  automatic serialization will be performed!
  
  // Set the "theme" cookie
  Cookie::set('theme', 'red');
  
  @param   string $name name of cookie
  @param   string $value value of cookie
  @param   integer $expiration lifetime in seconds
  @return  boolean
  @uses    Cookie::salt