code: public static function offset($remote, $local = null, $now = null) {
          if ($local === null) {
              // Use the default timezone
              $local = date_default_timezone_get();
          }
  
          if (is_int($now)) {
              // Convert the timestamp into a string
              $now = date(\DateTime::RFC2822, $now);
          }
  
          // Create timezone objects
          $zone_remote = new \DateTimeZone($remote);
          $zone_local = new \DateTimeZone($local);
  
          // Create date objects from timezones
          $time_remote = new \DateTime($now, $zone_remote);
          $time_local = new \DateTime($now, $zone_local);
  
          // Find the offset
          $offset = $zone_remote->getOffset($time_remote) - $zone_local->getOffset($time_local);
  
          return $offset;
      }
docs: Returns the offset (in seconds) between two time zones. Use this to
  display dates to users in different time zones.
  
  $seconds = Date::offset('America/Chicago', 'GMT');
  
  [!!] A list of time zones that PHP supports can be found at
  <http://php.net/timezones>.
  
  @param string $remote timezone that to find the offset of
  @param string $local timezone used as the baseline
  @param mixed $now UNIX timestamp or date string
  
  @return integer