code: func (s *SimAdapter) DialRPC(id enode.ID) (*rpc.Client, error) {
  	node, ok := s.GetNode(id)
  	if !ok {
  		return nil, fmt.Errorf("unknown node: %s", id)
  	}
  	handler, err := node.node.RPCHandler()
  	if err != nil {
  		return nil, err
  	}
  	return rpc.DialInProc(handler), nil
  }
docs: // DialRPC implements the RPCDialer interface by creating an in-memory RPC
  // client of the given node