@Override
    public String toString() {
        return "RANestedOutputStream" + "\nsegmentCount = " + segmentCount + "\n" + segmentOutputStream;
    }
Class used to write multiple streams to a single stream separated by segments
by a segment marker (boundary).
stroom-data/stroom-data-store-impl-fs/src/main/java/stroom/data/store/impl/fs/RANestedOutputStream.java