Adds benchmark test

Kubernetes-commit: 21ca6c498aec2879fd7b9796f55743e5f14d5a80

util/workqueue/delaying_queue_test.go

@@ -18,6 +18,7 @@ package workqueue
 
 import (
 	"fmt"
+	"math/rand"
 	"reflect"
 	"testing"
 	"time"
@@ -214,6 +215,25 @@ func TestCopyShifting(t *testing.T) {
 	}
 }
 
+func BenchmarkDelayingQueue_AddAfter(b *testing.B) {
+	r := rand.New(rand.NewSource(time.Now().Unix()))
+
+	fakeClock := clock.NewFakeClock(time.Now())
+	q := newDelayingQueue(fakeClock, "")
+
+	// Add items
+	for n := 0; n < b.N; n++ {
+		data := fmt.Sprintf("%d", n)
+		q.AddAfter(data, time.Duration(r.Int63n(int64(10*time.Minute))))
+	}
+
+	// Exercise item removal as well
+	fakeClock.Step(11 * time.Minute)
+	for n := 0; n < b.N; n++ {
+		_, _ = q.Get()
+	}
+}
+
 func waitForAdded(q DelayingInterface, depth int) error {
 	return wait.Poll(1*time.Millisecond, 10*time.Second, func() (done bool, err error) {
 		if q.Len() == depth {