@Override
    public void writeExternal(ObjectOutput out) throws IOException {
        conf.write(out);
        out.writeInt(splits.size());
        for (InputSplit split : splits) {
            ((HCatSplit) split).write(out);
        }
    }
This class contains the list of {@link InputSplit}s obtained
at master node and the configuration.
hcatalog/core/src/main/java/org/apache/hive/hcatalog/data/transfer/impl/ReaderContextImpl.java