anchor.diff:  await_client_blocked(Server, Client) ->
       receive
           {blocked, Client} ->
  -            p("received blocked message from client [~p] => "
  +            p("[await-client-blocked] "
  +              "received blocked message from client [~p] => "
                 "send continue to server [~p]~n", [Client, Server]),
               Server ! {continue, self()},
               ok;
   	{'EXIT', Client, CReason} ->
  +            p("[await-client-blocked] "
  +              "unexpected client (~p) exit: "
  +              "~n       ~p"
  +              "~n", [Client, CReason]),
   	    exit({client_crash, CReason});
   	{'EXIT', Server, SReason} ->
  +            p("[await-client-blocked] "
  +              "unexpected server (~p) exit: "
  +              "~n       ~p"
  +              "~n", [Server, SReason]),
   	    exit({server_crash, SReason})
       after 5000 ->
               %% There is no normal reason why this should take any time.
  
positive.code: sendreceive(Config) when is_list(Config) ->
      Pre = fun() ->
  		  p("create nodes"),
  		  ServerNode = make_node_name(server),
  		  ClientNode = make_node_name(client),
  		  Nodes = [ServerNode, ClientNode], 
  		  ok = ?START_NODES(Nodes),
  		  Nodes
  	  end,
      Case = fun(X) -> do_sendreceive(Config, X) end,
  
negative.code: block_unblock(Config) when is_list(Config) ->
      Pre = fun() ->
  		  p("create nodes"),
  		  ServerNode = make_node_name(t_bb_server),
  		  ClientNode = make_node_name(t_bb_client),
  		  Nodes = [ServerNode, ClientNode], 
  		  ok = ?START_NODES(Nodes, true),
  		  Nodes
  	  end,
      Case = fun(X) -> do_block_unblock(Config, X) end,
  