src/vs/base/common/strings.ts/doEqualsIgnoreCase
function doEqualsIgnoreCase(a: string, b: string, stopAt = a.length): boolean {
	for (let i = 0; i < stopAt; i++) {
		const codeA = a.charCodeAt(i);
		const codeB = b.charCodeAt(i);

		if (codeA === codeB) {
			continue;
		}

		// a-z A-Z
		if (isAsciiLetter(codeA) && isAsciiLetter(codeB)) {
			const diff = Math.abs(codeA - codeB);
			if (diff !== 0 && diff !== 32) {
				return false;
			}
		}

		// Any other charcode
		else {
			if (String.fromCharCode(codeA).toLowerCase() !== String.fromCharCode(codeB).toLowerCase()) {
				return false;
			}
		}
	}

	return true;
}