Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xls.php
private static function encodeUTF16($string, $compressed = false)
    {
        if ($compressed) {
            $string = self::uncompressByteString($string);
        }

        return StringHelper::convertEncoding($string, 'UTF-8', 'UTF-16LE');
    }
private static function encodeUTF16($string, $compressed = false)
    {
        if ($compressed) {
            $string = self::uncompressByteString($string);
        }

        return StringHelper::convertEncoding($string, 'UTF-8', 'UTF-16LE');
    }
Get UTF-8 string from (compressed or uncompressed) UTF-16 string.

@param string $string
@param bool $compressed

@return string