@Override
    protected void doApply(ApiResponse response, IPolicyContext context, CachingResourcesConfig config,
                           IPolicyChain<ApiResponse> chain) {
        chain.doApply(response);
    }
@see AbstractMappedPolicy#doApply(ApiResponse, IPolicyContext, Object, IPolicyChain)
gateway/engine/policies/src/main/java/io/apiman/gateway/engine/policies/CachingResourcesPolicy.java