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Compatibility, Deprecation, and Migration Plan 

• Backward Compatibility
  New interface, No backward compatibility

• Deprecation
  N/A
• Migration for Existing Deployments
  N/A. The feature is optional

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We can use follow tests to cover the change:

Integration Tests:  Add one log goal's implement for the interface and test with deployment

Unit test:  Test cover the exception handle part.

Rejected Alternatives

Alternative 1:  Use the client consume rebalance listener
Relying on client-side behavior is operationally fragile. In practice, callback availability and behavior depend on SDK adoption and upgrade cycles, which are difficult to control sometimes. Even when teams implemented the callback with log only. users may reduce or disable the logs by mistake or some other reasons. This creates a common failure mode: when incidents occur, critical rebalance evidence is missing at the client side, making diagnosis slow and uncertain

Alternative 2:  Enhance the existed server side metric

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