anchor.diff:    case Sock#socket.tcp_state of
       syn_rcvd ->
         ?SET(Id, tcp_state, established),
  +      ?APPLY(set_synchronized, [false]),  %% avoiding race with close()
         P = Sock#socket.parent,
         case get_socket(S, P) of
           #socket{blocked = [Pid | Pids]} ->
  
positive.code:   case get_socket(S, Id) of
      Sock = #socket{} ->
        Sock#socket.socket == Socket andalso
        Sock#socket.tcp_state == listen;
      false -> false
    end.
  
  
negative.code:                socket_type, seq, rcvd, rseq, id, parent, blocked = [],
                 accept_queue = []}).
  
  -record(state, {ip, sockets = [], synchronized = true}).
  
  initial_state() ->
    #state{}.
  