code: func (c *Cluster) WaitContainer(id string) (int, error) {
  	node, err := c.getNodeForContainer(id)
  	if err != nil {
  		return -1, err
  	}
  	node.setPersistentClient()
  	code, err := node.WaitContainer(id)
  	return code, wrapError(node, err)
  }
docs: // WaitContainer blocks until the given container stops, returning the exit
  // code of the container command.