code: @Override
  	public void write(T result, HttpServerRequest request, HttpServerResponse response) {
  
  		if (result != null) {
  			response.end(JsonUtils.toJson(result, io.vertx.core.json.Json.mapper));
  		}
  		else {
  			response.end();
  		}
  	}
docs: TODO: add custom mapper ... to override vertx.mapper if desired