@Override
    public void startStream() {
        buffer = true;
        hasFiredEvents = false;
        inRoot = false;
        length = 0;
        afterRoot = -1;
        depth = 0;
        count = 0;
        if (locationHolder != null) {
            locationHolder.reset();
        }

        super.startStream();
    }
This method tells filters that a stream is about to be parsed so that
they can complete any setup necessary.
stroom-pipeline/src/main/java/stroom/pipeline/filter/SplitFilter.java