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• A new field committedVoterStates of type Map<Integer, ReplicaState> is added to the LeaderState class. This field stores the voter states.

• Within the maybeUpdateHighWatermark() method, once the leader advances advance the HighWatermark, the committedVoterStates map is updated to a copy of the current active currentVoterStates. This ensures the committed voter set reflects the durable state of membership at the last committed log entry.

• The distinction between currentVoterStates (potentially changing during ongoing elections or reconfigurations) and committedVoterStates (stable, committed membership) enables clear separation of transient membership changes from those that are confirmed and durable.

• An accessor method committedVoterStates() is provided on LeaderState to expose this value. This method is used when constructing DescribeQuorumResponse messages to include the committed voter set, improving observability and operational diagnostics.

• In certain cases, such as quorum startup or fetching snapshots, the value of committedVoterStates may not be available. When handling a DescribeQuorumRequest in these situations, we should read the committed voters from the replicatedLog using the replicatedLog#startOffsetreplicatedLog#highWatermark. However, since there is no information for logEndOffset, lastFetchTimestamp, or lastCaughtUpTimestamp, these fields will return their default value of -1.
  
  This mechanism strengthens the Raft membership model by making committed membership explicit and accessible to tooling and clients, thereby improving cluster state transparency.

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