public function truncate($length, $substring = '')
{
$stringy = static::create($this->str, $this->encoding);
if ($length >= $stringy->length()) {
return $stringy;
}
// Need to further trim the string so we can append the substring
$substringLength = \mb_strlen($substring, $stringy->encoding);
$length = $length - $substringLength;
$truncated = \mb_substr($stringy->str, 0, $length, $stringy->encoding);
$stringy->str = $truncated . $substring;
return $stringy;
}