@Override
    public Response process(Request request, Execution execution) {
        Response response=execution.process(request);
        response.data().completeFuture().whenComplete((__, ___) -> new RunnableExecution(request,
                new ExecutionWithResponse(asyncChain, response, execution)).run());
        return response;
    }
A processor which registers a listener on the future completion of
asynchronously arriving data to perform another chain at that point.
container-core/src/test/java/com/yahoo/processing/test/documentation/AsyncDataProcessingInitiator.java