presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/hourFromTimeWithTimeZone
class DateTimeFunctions:    @Description("hour of the day of the given time")
    @ScalarFunction("hour")
    @SqlType(StandardTypes.BIGINT)
    public static long hourFromTimeWithTimeZone(@SqlType(StandardTypes.TIME_WITH_TIME_ZONE) long timeWithTimeZone)
    {
        return unpackChronology(timeWithTimeZone).hourOfDay().get(unpackMillisUtc(timeWithTimeZone));
    }