@Override
        public com.yahoo.processing.Response process(com.yahoo.processing.Request request, Execution execution) {
            com.yahoo.processing.Response response = execution.process(request);
            List<Data> dataList = response.data().asList();
            for (Data data : dataList) {
                if ( ! (data instanceof MapData)) continue;
                MapData mapData = (MapData)data;
                mapData.map().put("streamProcessed",Boolean.TRUE);
            }
            return response;
        }
Tests that the ResponseStatus takes precedence over errors
container-core/src/test/java/com/yahoo/processing/handler/ProcessingHandlerTestCase.java