code: func (l *SSHTunnelList) Close() {
  	for ix := range l.entries {
  		entry := l.entries[ix]
  		go func() {
  			defer HandleCrash()
  			time.Sleep(1 * time.Minute)
  			if err := entry.Tunnel.Close(); err != nil {
  				glog.Errorf("Failed to close tunnel %v: %v", entry, err)
  			}
  		}()
  	}
  }
docs: // Close asynchronously closes all tunnels in the list after waiting for 1
  // minute. Tunnels will still be open upon this function's return, but should
  // no longer be used.