anchor.diff:                     end},
            #{desc => "create listen socket",
              cmd  => fun(#{domain := Domain,
  -                         type   := Type,
                            proto  := Proto} = State) ->
  -                           case socket:open(Domain, Type, Proto) of
  +                           case socket:open(Domain, stream, Proto) of
                                  {ok, Sock} ->
                                      {ok, State#{lsock => Sock}};
                                  {error, _} = ERROR ->
  
positive.code:                                   socket:recv(Sock)
                            end,
                     InitState = #{domain => local,
                                   type   => stream,
                                   proto  => default,
                                   send   => Send,
                                   recv   => Recv},
  
negative.code:                                   end
                            end,
                     InitState = #{domain => inet,
                                   proto  => udp,
                                   send   => Send,
                                   recv   => Recv},
                     ok = api_b_send_and_recv_udp(InitState)
  