@Override
        public String toString() {
            return String.format(
                "VoterNode(voterKey=%s, listeners=%s, supportedKRaftVersion=%s)",
                voterKey,
                listeners,
                supportedKRaftVersion
            );
        }
Returns the listeners of the voter node
raft/src/main/java/org/apache/kafka/raft/internals/VoterSet.java