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To make sure we could recover from broker failure/leader transition, an in-memory member name map is not enough. We would reuse the `_consumer_offsets` topic to store the static member map information. When another broker takes over the leadership, we could transfer the mapping together. We shall also introduce new member metadata format:

private val MEMBER_METADATA_V3 = new Schema(
  new Field(MEMBER_ID_KEY, STRING),
  new Field(MEMBER_NAME_KEY, STRING), // new
  new Field(CLIENT_ID_KEY, STRING),
  new Field(CLIENT_HOST_KEY, STRING),
  new Field(REBALANCE_TIMEOUT_KEY, INT32),
  new Field(SESSION_TIMEOUT_KEY, INT32),
  new Field(SUBSCRIPTION_KEY, BYTES),
  new Field(ASSIGNMENT_KEY, BYTES))

command line APIs for membership management

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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.

We need to enforce special access to these APIs to the end user who may not be in administrative role of Kafka Cluster. This involves defining some customized Kafka principle.

Compatibility, Deprecation, and Migration Plan

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