@Override
    public String toString() {
        return "PersisterStateBatch(" +
                "firstOffset=" + firstOffset + "," +
                "lastOffset=" + lastOffset + "," +
                "deliveryState=" + deliveryState + "," +
                "deliveryCount=" + deliveryCount +
                ")";
    }
This class contains the information for a single batch of state information for use by the {@link Persister}.
server-common/src/main/java/org/apache/kafka/server/group/share/PersisterStateBatch.java