@Override
public void open(FileInputSplit split) throws IOException {
super.open(split);
DatumReader<GenericRecord> datumReader = new GenericDatumReader<GenericRecord>();
SeekableInput in = new FSDataInputStreamWrapper(stream, (int) split.getLength());
LOG.info("Opening split " + split);
dataFileReader = DataFileReader.openReader(in, datumReader);
dataFileReader.sync(split.getStart());
}