presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/timeAtTimeZone
class DateTimeFunctions:    @ScalarFunction(value = "at_timezone", hidden = true)
    @SqlType(StandardTypes.TIME_WITH_TIME_ZONE)
    public static long timeAtTimeZone(ConnectorSession session, @SqlType(StandardTypes.TIME_WITH_TIME_ZONE) long timeWithTimeZone, @SqlType(StandardTypes.INTERVAL_DAY_TO_SECOND) long zoneOffset)
    {
        checkCondition((zoneOffset % 60_000L) == 0L, INVALID_FUNCTION_ARGUMENT, "Invalid time zone offset interval: interval contains seconds");
        long zoneOffsetMinutes = zoneOffset / 60_000L;
        return timeAtTimeZone(session, timeWithTimeZone, getTimeZoneKeyForOffset(zoneOffsetMinutes));
    }