@Override
    public String toString() {
        return "OffsetAndTimestampInternal{" +
                "timestamp=" + timestamp +
                ", offset=" + offset +
                ", leaderEpoch=" + leaderEpoch +
                '}';
    }
Internal representation of {@link OffsetAndTimestamp} to allow negative timestamps and offset.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/OffsetAndTimestampInternal.java