@Override
    public void setConf(final Configuration config) {
        this.conf = config;
    }
This contains information obtained at master node to help prepare slave nodes
for writer. This class implements {@link Externalizable} so it can be
serialized using standard java mechanisms. Master should serialize it and
make it available to slaves to prepare for writes.
hcatalog/core/src/main/java/org/apache/hive/hcatalog/data/transfer/impl/WriterContextImpl.java