@Override
    public String toString() {
        return "RecordBatch(magic=" + magic() + ", offsets=[" + baseOffset() + ", " + lastOffset() + "], " +
                "sequence=[" + baseSequence() + ", " + lastSequence() + "], " +
                "isTransactional=" + isTransactional() + ", isControlBatch=" + isControlBatch() + ", " +
                "compression=" + compressionType() + ", timestampType=" + timestampType() + ", crc=" + checksum() + ")";
    }
Gets the base timestamp of the batch which is used to calculate the record timestamps from the deltas.

@return The base timestamp
clients/src/main/java/org/apache/kafka/common/record/DefaultRecordBatch.java