getTimezoneOffsetFromTimezone (timeZone) {
		const str = new Date().toLocaleString("en", { timeZone, timeZoneName: "longOffset" });
		Log.debug("tz offset=", str);
		const [_, h, m] = str.match(/([+-]\d+):(\d+)$/) || ["", "+00", "00"];
		return h * 60 + (h > 0 ? +m : -m);
	}
get the timezone offset from the timezone string

@param the timezone string
@returns the numerical offset