anchor.diff:  %%
   %% Anything but ACK
   %%
  -init([Request, Socket, LogStr, AppModule, Mode]) when record(Request, request) ->
  +init([Request, Socket, LogStr, _AppModule, Mode]) when record(Request, request) ->
       {Method, URI} = {Request#request.method, Request#request.uri},
       Branch = siprequest:generate_branch() ++ "-UAS",
       LogTag = Branch ++ " " ++ Method,
  
positive.code: %% Purpose: Convert process state when code is changed
  %% Returns: {ok, NewState}
  %%--------------------------------------------------------------------
  code_change(OldVsn, State, Extra) ->
      {ok, State}.
  
  %%--------------------------------------------------------------------
  
negative.code: %%
  %% ACK - no go
  %%
  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.
  