@Override
    public String toString() {
        return "QuorumInfo(" +
            "leaderId=" + leaderId +
            ", leaderEpoch=" + leaderEpoch +
            ", highWatermark=" + highWatermark +
            ", voters=" + voters +
            ", observers=" + observers +
            ", nodes=" + nodes +
            ')';
    }
@return The voter nodes in the Raft cluster, or an empty map if KIP-853 is not enabled.
clients/src/main/java/org/apache/kafka/clients/admin/QuorumInfo.java