code: @Internal
      public static Optional<NettyMutableHttpResponse> set(NettyHttpRequest<?> request, HttpResponse<?> response) {
          request.attr(KEY).set((NettyMutableHttpResponse) response);
          return Optional.ofNullable((NettyMutableHttpResponse) response);
      }
docs: Lookup the response from the request.
  
  @param request  The request
  @param response The Http Response
  @return The {@link NettyMutableHttpResponse}