anchor.diff:    ok = gen_tcp:send(Socket, Packet).
   
   %% @private
  -increment(SeqNum) ->
  -  SeqNum + 1.
  +increment(Seq) ->
  +  Seq + 1.
  
positive.code: handle_info({tcp_closed, _Socket}, State) ->
    {noreply, State#state{
      connected = false,
      binding   = 0
    }};
  
  
negative.code: %% @private submit_sm packet sending
  %% ----------------------------------------------------------------------------
  handle_call({submit_sm, SubmitSm, _Options}, From, 
               #state{socket=Socket, seq_num=Seq, from_list=Clients} = State) ->
    NewSeq = increment(Seq),
    {pdu, Packet} = esmpp_pdu:submit_sm(NewSeq, SubmitSm), 
    send(Socket, Packet),
    NewClients = maps:put(NewSeq, From, Clients),
    {noreply, State#state{
      from_list = NewClients,
      seq_num   = NewSeq
    }}; 
  
  %% ----------------------------------------------------------------------------
  