presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/millisecondFromTimestampWithTimeZone
class DateTimeFunctions:    @Description("millisecond of the second of the given timestamp")
    @ScalarFunction("millisecond")
    @SqlType(StandardTypes.BIGINT)
    public static long millisecondFromTimestampWithTimeZone(@SqlType(StandardTypes.TIMESTAMP_WITH_TIME_ZONE) long timestampWithTimeZone)
    {
        // No need to check the associated zone here. A zone always has offset of whole minutes.
        return MILLISECOND_OF_SECOND.get(unpackMillisUtc(timestampWithTimeZone));
    }