This is a client-go example of https://kubernetes.io/docs/tasks/administer-cluster/extended-resource-node/

patch-extended-resource.go

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"path/filepath"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	types "k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
	"k8s.io/klog/v2"
)

// This is a client-go example of https://kubernetes.io/docs/tasks/administer-cluster/extended-resource-node/
// Run `./patch-extended-resource -v 10 -n <nodeName>`

var (
	nodeName  = ""
	jsonPatch = `[
		{
			"op": "add",
			"path": "/status/capacity/example.com~1dongle",
			"value": "4"
		}
	]`
	subresourceStatus = "status"
)

func main() {
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" {
		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file")
	} else {
		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
	}
	flag.StringVar(&nodeName, "n", "kind-worker", "node name")

	klog.InitFlags(nil)
	flag.Parse()

	// use the current context in kubeconfig
	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
	if err != nil {
		panic(err.Error())
	}

	// create the clientset
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		log.Fatalln("create client", err.Error())
	}

	// let's patch
	node, err := clientset.CoreV1().Nodes().Patch(context.TODO(), nodeName, types.JSONPatchType, []byte(jsonPatch), metav1.PatchOptions{}, subresourceStatus)
	if err != nil {
		log.Fatalln("patch status", err.Error())
	}

	// print result
	fmt.Println("Capacity", node.Status.Capacity)
	fmt.Println("Allocatable", node.Status.Allocatable)
}