@Override
    public CloseableIterator<Record> streamingIterator(BufferSupplier bufferSupplier) {
        if (isCompressed())
            return compressedIterator(bufferSupplier, false);
        else
            return uncompressedIterator();
    }
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