public function startsWithIgnoreCase($substring) {
		$substring = mb_strtolower($substring, $this->encoding);
		$substringLength = mb_strlen($substring, $this->encoding);
		$startOfStr = mb_strtolower(mb_substr($this->string, 0, $substringLength, $this->encoding));

		return (string) $substring === $startOfStr;
	}