src/vs/base/common/uri.ts/URI/file
class URI:	static file(path: string): URI {

		let authority = _empty;

		// normalize to fwd-slashes on windows,
		// on other systems bwd-slashes are valid
		// filename character, eg /f\oo/ba\r.txt
		if (isWindows) {
			path = path.replace(/\\/g, _slash);
		}

		// check for authority as used in UNC shares
		// or use the path as given
		if (path[0] === _slash && path[1] === _slash) {
			const idx = path.indexOf(_slash, 2);
			if (idx === -1) {
				authority = path.substring(2);
				path = _slash;
			} else {
				authority = path.substring(2, idx);
				path = path.substring(idx) || _slash;
			}
		}

		return new Uri('file', authority, path, _empty, _empty);
	}