code: func (c *Client) removeCallbacks(callbacks map[string]dnode.Path) {
  	for sid := range callbacks {
  		// We don't check for error because we have created
  		// the callbacks map in the send function above.
  		// It does not come from remote, so cannot contain errors.
  		id, _ := strconv.ParseUint(sid, 10, 64)
  		c.scrubber.RemoveCallback(id)
  	}
  }
docs: // Used to remove callbacks after error occurs in send().