CSupportTimetableCache::GetTimeZoneOffset

static function GetTimeZoneOffset()
{
	if(self::$timeZoneOffset === null)
	{
		if(self::Possible())
		{
			$localTime = new DateTime();
			$localOffset = $localTime->getOffset();
			$serverTime = new DateTime(null, self::GetTimeZone());
			self::$timeZoneOffset = $serverTime->getOffset() - $localOffset;
		}
		else 
		{
			self::$timeZoneOffset = 0;
		}
	}
	return self::$timeZoneOffset;
}