presto-orc/src/main/java/io/prestosql/orc/reader/ByteColumnReader.java/ByteColumnReader/readNullBlock
class ByteColumnReader:    private Block readNullBlock(boolean[] isNull, int nonNullCount)
            throws IOException
    {
        verifyNotNull(dataStream);
        int minNonNullValueSize = minNonNullValueSize(nonNullCount);
        if (nonNullValueTemp.length < minNonNullValueSize) {
            nonNullValueTemp = new byte[minNonNullValueSize];
            systemMemoryContext.setBytes(sizeOf(nonNullValueTemp));
        }

        dataStream.next(nonNullValueTemp, nonNullCount);

        byte[] result = ReaderUtils.unpackByteNulls(nonNullValueTemp, isNull);

        return new ByteArrayBlock(nextBatchSize, Optional.of(isNull), result);
    }