code: func (mc CommunicatingPlugin) Reserve(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
  	if pod == nil {
  		return framework.NewStatus(framework.Error, "pod cannot be nil")
  	}
  	if pod.Name == "my-test-pod" {
  		pc.Lock()
  		pc.Write(framework.ContextKey(pod.Name), "never bind")
  		pc.Unlock()
  	}
  	return nil
  }
docs: // Reserve is the functions invoked by the framework at "reserve" extension point.