@Override
                protected Record doReadRecord(long baseOffset, long baseTimestamp, int baseSequence, Long logAppendTime) throws IOException {
                    return DefaultRecord.readPartiallyFrom(inputStream, baseOffset, baseTimestamp, baseSequence, logAppendTime);
                }
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