[DISCUSS] PIP-258: Deprecation of the consumer subscribeTopicMode configuration

[Baodi Shi]

Hi all,

I've started a PIP to discuss: PIP-258: Deprecation of the consumer
subscribeTopicMode configuration

### Motivation

About pattern subscribes of consumers, the `topicsPattern` and
`subscribeTopicMode` configurations are contradictory.

For example, the `topicsPattern` represents only subscription to
`persistent topic`, but the `subscriptionTopicsMode` represents
subscription to `all topic`.

``` java
Pattern pattern =
Pattern.compile("persistent://my-property/my-ns/pattern-topic.*");
Consumer<byte[]> consumer = pulsarClient.newConsumer()
            .topicsPattern(pattern)
            .subscriptionTopicsMode(RegexSubscriptionMode.AllTopics)
            .build();
```

Finally, `all topics` are subscribed. It's very confusing.


For more details, please read the PIP at
https://github.com/apache/pulsar/issues/19798
<https://github.com/apache/pulsar/issues/19601>


Thanks,
Baodi Shi