[improve][pip] PIP-426: Enhanced Consumer Throttling and Unacknowledged Message Tracking for Exclusive and Failover Subscriptions

[berg223]

Fixes https://github.com/apache/pulsar/issues/24159

Main Issue: https://github.com/apache/pulsar/issues/24159

Motivation

1. I have tried to fix the issue by https://github.com/apache/pulsar/pull/24376. However, that PR doesn't support features about cumulative ack, batching mode, and transaction. So I want to improve it further.
2. I have found another issue that flowcontrol of exclusive or failover consumer is not work. Since the issues are highly correlated, I want to fix them at the same time.

Modifications

1. Remove the Subscription.isIndividualAckMode() restriction that limits pendingAcks usage to shared subscriptions.
2. Extend PendingAckHandleImpl for exclusive/failover consumers.
3. Enhance flow control in PersistentDispatcherSingleActiveConsumer

Verifying this change

• [X] Make sure that the change passes the CI checks.

Does this pull request potentially affect one of the following parts:

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• [ ] Dependencies (add or upgrade a dependency)
• [ ] The public API
• [ ] The schema
• [ ] The default values of configurations
• [ ] The threading model
• [ ] The binary protocol
• [ ] The REST endpoints
• [ ] The admin CLI options
• [ ] The metrics
• [ ] Anything that affects deployment

Documentation

• [ ] doc
• [ ] doc-required
• [X] doc-not-needed
• [ ] doc-complete

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