@Override
    public void startProcessing() {
        if (hdfsUri == null) {
            throw new RuntimeException("No URI has been supplied for the Hadoop Distributed File System");
        }
        // conf = new Configuration();

        super.startProcessing();
    }
Creates an output stream for a file on an Hadoop Distributed File System
<p>
TODO Need to add in proper security so it can connect to a secured
(kerberos?) cluster
stroom-pipeline/src/main/java/stroom/pipeline/writer/HDFSFileAppender.java