code: func (c *Cluster) AttachToContainerNonBlocking(opts docker.AttachToContainerOptions) (docker.CloseWaiter, error) {
  	node, err := c.getNodeForContainer(opts.Container)
  	if err != nil {
  		return nil, err
  	}
  	node.setPersistentClient()
  	return node.AttachToContainerNonBlocking(opts)
  }
docs: // AttachToContainerNonBlocking attaches to a container and returns a docker.CloseWaiter, using given options.