code: func (n *Node) raftApplyCommand(cmd redcon.Command) (interface{}, error) {
  	f := n.raft.Apply(cmd.Raw, raftTimeout)
  	if err := f.Error(); err != nil {
  		return nil, err
  	}
  	// we check for the response to be an error and return it as such.
  	switch v := f.Response().(type) {
  	default:
  		return v, nil
  	case error:
  		return nil, v
  	}
  }
docs: // raftApplyCommand encodes a series of args into a raft command and
  // applies it to the index.