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forceStaticRebalance will trigger one rebalance immediately on static membership, which is mainly used for fast scale up/down cases. Error will be returned if 

1. the broker is on an old version.
2. if the group is preparing rebalance/completing rebalance.
3. group is on dynamic membership.
4. other potential failure cases. This is mainly used for fast scale up/down cases.

Compatibility, Deprecation, and Migration Plan

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