public static SubscriptionState createSubscriptionState(ConsumerConfig config, LogContext logContext) {
        String s = config.getString(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG).toUpperCase(Locale.ROOT);
        OffsetResetStrategy strategy = OffsetResetStrategy.valueOf(s);
        return new SubscriptionState(logContext, strategy);
    }
A fixed, large enough value will suffice for max.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/ConsumerUtils.java