anchor.diff:  %%
   %% ACK - no go
   %%
  -init([Request, Socket, LogStr, AppModule, Mode]) when record(Request, request), Request#request.method == "ACK" ->
  +init([Request, _Socket, _LogStr, _AppModule, _Mode]) when record(Request, request), Request#request.method == "ACK" ->
       %% Although a bit vague, RFC3261 section 17 (Transactions) do say that
       %% it is not allowed to send responses to ACK requests, so we simply
       %% deny to start a server transaction here.
  
positive.code: 
  %% This branch should answer something.
  send_response(Response, SendReliably, State) when record(Response, response), record(State, state) ->
      {Status, Reason, RHeader, RBody} = {Response#response.status, Response#response.reason, Response#response.header, Response#response.body},
      Request = State#state.request,
      {Method, URI} = {Request#request.method, Request#request.uri},
      Socket = State#state.socket,
  
negative.code:     OldSipState = State#state.sipstate,
      {Status, Reason} = {Response#response.status, Response#response.reason},
      NewState1 = go_stateful(Created, ResponseToMethod, Status, LogTag, State),
      NewState = 
  	case catch send_response_statemachine(ResponseToMethod, Status, OldSipState) of
  	    {Action, SendReliably, NewSipState} when Action == ignore; Action == send ->
  		NewState2 = case Action of
  				ignore ->
  				    NewState1;
  				send ->
  				    LogLevel = if
  						   Status >= 200 -> normal;
  						   true -> debug
  					       end,
  				    What = case Created of
  					       created -> "Responding";
  					       _ -> "Forwarding response"
  					   end,
  				    logger:log(LogLevel, "~s: ~s ~p ~s",
  					       [LogTag, What, Status, Reason]),
  				    {ok, NewState2_1} = send_response(Response, SendReliably, NewState1),
  				    NewState2_1
  			    end,
  		enter_sip_state(NewSipState, NewState2);
  	    E ->
  		logger:log(error, "~s: State machine does not allow us to send '~p ~s' in response to '~s ~s' when my SIP-state is '~p'",
  			   [LogTag, Status, Reason, ResponseToMethod, sipurl:print(ResponseToURI), OldSipState]),
  		logger:log(debug, "~s: State machine returned :~n~p", [LogTag, E]),
  		NewState1
  	end,
      {ok, NewState}.
  
  go_stateful(created, Method, Status, LogTag, State) when record(State, state), State#state.mode == stateless, Status >= 200 ->
  