@Override
    public String toString() {
        final String str =
            "StreamsMetadata {" +
                "hostInfo=" + hostInfo +
                ", stateStoreNames=" + stateStoreNames +
                ", topicPartitions=" + topicPartitions +
                ", standbyStateStoreNames=" + standbyStateStoreNames +
                ", standbyTopicPartitions=" + standbyTopicPartitions;
        if (topologyName == null) {
            return str + '}';
        } else {
            return str +
                ", topologyName=" + topologyName +
                '}';
        }
    }
State stores owned by the instance as a standby replica

@return set of standby state store names
streams/src/main/java/org/apache/kafka/streams/state/internals/StreamsMetadataImpl.java