Sample Controller: Use one variable for key throughout

After changing it to use a typed workqueue, the differentiation between
the key we get from the workqueue and they key we use down the line is
no longer useful as they are the same, so use one variable for it
throughout.

staging/src/k8s.io/sample-controller/controller.go

@@ -204,27 +204,27 @@ func (c *Controller) processNextWorkItem(ctx context.Context) bool {
 	}
 
 	// We wrap this block in a func so we can defer c.workqueue.Done.
-	err := func(key string) error {
+	err := func() 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.workqueue.Done(key)
+		defer c.workqueue.Done(obj)
 		// Run the syncHandler, passing it the namespace/name string of the
 		// Foo resource to be synced.
-		if err := c.syncHandler(ctx, key); err != nil {
+		if err := c.syncHandler(ctx, obj); err != nil {
 			// Put the item back on the workqueue to handle any transient errors.
-			c.workqueue.AddRateLimited(key)
-			return fmt.Errorf("error syncing '%s': %s, requeuing", key, err.Error())
+			c.workqueue.AddRateLimited(obj)
+			return fmt.Errorf("error syncing '%s': %s, requeuing", obj, err.Error())
 		}
 		// Finally, if no error occurs we Forget this item so it does not
 		// get queued again until another change happens.
 		c.workqueue.Forget(obj)
-		logger.Info("Successfully synced", "resourceName", key)
+		logger.Info("Successfully synced", "resourceName", obj)
 		return nil
-	}(obj)
+	}()
 
 	if err != nil {
 		utilruntime.HandleError(err)