private LoadBalancer.PickResult getErrorPickResult() {
        if (hasIdleNode) {
            return LoadBalancer.PickResult.withNoResult();
        } else {
            return LoadBalancer.PickResult.withError(
                    Status.UNAVAILABLE.withCause(new NoSuchElementException()).withDescription("can not find the subChannel")
            );
        }
    }
Choose subChannel.

@param list subChannel list
@return result subChannel
shenyu-plugin/shenyu-plugin-proxy/shenyu-plugin-rpc/shenyu-plugin-grpc/src/main/java/org/apache/shenyu/plugin/grpc/loadbalance/picker/AbstractReadyPicker.java