Merge pull request #65609 from CaoShuFeng/sample-controller

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

fix sample-controller README

The guide in doc causes an error
```
$ go run *.go -kubeconfig=$HOME/.kube/config
go run: cannot run *_test.go files (controller_test.go)
```

**What this PR does / why we need it**:

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

Kubernetes-commit: cf14f027c59f50c897ae5b6bb5a1f69581d1549b

vendor/k8s.io/apimachinery/pkg/util/net/http.go

@@ -91,7 +91,8 @@ func SetOldTransportDefaults(t *http.Transport) *http.Transport {
 		// ProxierWithNoProxyCIDR allows CIDR rules in NO_PROXY
 		t.Proxy = NewProxierWithNoProxyCIDR(http.ProxyFromEnvironment)
 	}
-	if t.DialContext == nil {
+	// If no custom dialer is set, use the default context dialer
+	if t.DialContext == nil && t.Dial == nil {
 		t.DialContext = defaultTransport.DialContext
 	}
 	if t.TLSHandshakeTimeout == 0 {
@@ -129,7 +130,18 @@ func DialerFor(transport http.RoundTripper) (DialFunc, error) {
 
 	switch transport := transport.(type) {
 	case *http.Transport:
-		return transport.DialContext, nil
+		// transport.DialContext takes precedence over transport.Dial
+		if transport.DialContext != nil {
+			return transport.DialContext, nil
+		}
+		// adapt transport.Dial to the DialWithContext signature
+		if transport.Dial != nil {
+			return func(ctx context.Context, net, addr string) (net.Conn, error) {
+				return transport.Dial(net, addr)
+			}, nil
+		}
+		// otherwise return nil
+		return nil, nil
 	case RoundTripperWrapper:
 		return DialerFor(transport.WrappedRoundTripper())
 	default: