code: func (proxier *Proxier) shutdown() {
  	proxier.mu.Lock()
  	defer proxier.mu.Unlock()
  
  	for serviceName, info := range proxier.serviceMap {
  		proxier.stopProxy(serviceName, info)
  	}
  	proxier.cleanupStaleStickySessions()
  	close(proxier.stopChan)
  }
docs: // shutdown closes all service port proxies and returns from the proxy's
  // sync loop. Used from testcases.