@Override
    public void flush() throws IOException {
        try {
            dataOutputStream.flush();
        } finally {
            if (indexOutputStream != null) {
                indexOutputStream.flush();
            }
        }
    }
Flushes the data and index output streams.
stroom-data/stroom-data-store-impl-fs/src/main/java/stroom/data/store/impl/fs/RASegmentOutputStream.java