public static function unicodeToHex($char){

		if(!is_string($char) || mb_strlen($char, 'utf-8') !== 1){
			throw new \InvalidArgumentException('$char must be one single character');
		}

		$unicode = unpack('N', mb_convert_encoding($char, 'UCS-4BE', 'UTF-8'));
		return dechex($unicode[1]);

	}