@SuppressWarnings("unchecked")
    @Override
    public Response process(Request request, Execution execution) {
        List<FutureResponse> futureResponses=new ArrayList<>(chains.size());
        for (Chain<? extends Processor> chain : chains) {
            futureResponses.add(new AsyncExecution(chain,execution).process(request));
        }
        Response response=execution.process(request);
        AsyncExecution.waitForAll(futureResponses,1000);
        for (FutureResponse futureResponse : futureResponses) {
            Response federatedResponse=futureResponse.get();
            response.data().add(federatedResponse.data());
            response.mergeWith(federatedResponse);
        }
        return response;
    }
Call a number of chains in parallel
container-core/src/test/java/com/yahoo/processing/test/documentation/Federator.java