You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: controller.go
    path of file: ./repos/kubernetes/staging/src/k8s.io/apiserver/pkg/admission/plugin/policy/internal/generic
    
    the code of the file until where you have to start completion: /*
Copyright 2022 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package generic

import (
	"context"
	"errors"
	"fmt"
	"sync"
	"sync/atomic"
	"time"

	kerrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"

	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/cache/synctrack"
	"k8s.io/client-go/util/workqueue"
	"k8s.io/klog/v2"
)

var _ Controller[runtime.Object] = &controller[runtime.Object]{}

type controller[T runtime.Object] struct {
	informer Informer[T]
	queue    workqueue.RateLimitingInterface

	// Returns an error if there was a transient error during reconciliation
	// and the object should be tried again later.
	reconciler func(namespace, name string, newObj T) error

	options ControllerOptions

	// must hold a func() bool or nil
	notificationsDelivered atomic.Value

	hasProcessed synctrack.AsyncTracker[string]
}

type 
    
func (c *controller[T]) runWorker() {
	for {
		key, shutdown := c.queue.Get()
		if shutdown {
			return
		}

		// We wrap this block in a func so we can defer c.workqueue.Done.
		err := func(obj interface{}) error {
			// We call Done here so the workqueue knows we have finished
			// processing this item. We also must remember to call Forget if we
			// do not want this work item being re-queued. For example, we do
			// not call Forget if a transient error occurs, instead the item is
			// put back on the workqueue and attempted again after a back-off
			// period.
			defer c.queue.Done(obj)
			var key string
			var ok bool
			// We expect strings to come off the workqueue. These are of the
			// form namespace/name. We do this as the delayed nature of the
			// workqueue means the items in the informer cache may actually be
			// more up to date that when the item was initially put onto the
			// workqueue.
			if key, ok = obj.(string); !ok {
				// How did an incorrectly formatted key get in the workqueue?
				// Done is sufficient. (Forget resets rate limiter for the key,
				// but the key is invalid so there is no point in doing that)
				return fmt.Errorf("expected string in workqueue but got %#v", obj)
			}
			defer c.hasProcessed.Finished(key)

			if err := c.reconcile(key); err != nil {
				// Put the item back on the workqueue to handle any transient errors.
				c.queue.AddRateLimited(key)
				return fmt.Errorf("error syncing '%s': %s, requeuing", key, err.Error())
			}
			// Finally, if no error occurs we Forget this item so it is allowed
			// to be re-enqueued without a long rate limit
			c.queue.Forget(obj)
			klog.V(4).Infof("syncAdmissionPolicy(%q)", key)
			return nil
		}(key)

		if err != nil {
			utilruntime.HandleError(err)
		}
	}
}