anchor.diff:  %%           State  = trying | calling | proceeding | completed |
   %%                    terminated
   %%--------------------------------------------------------------------
  -received_response_state_machine(Method, Status, State) when Status =< 99 ->
  -    logger:log(debug, "UAC decision: Received INVALID response ~p to ~p when in state '~p', ignoring",
  -	       [Status, Method, State]),
  -    {ignore, State};
  -
  -
  -received_response_state_machine(Method, Status, calling) when Status == 100 ->
  -    logger:log(debug, "UAC decision: Received 100 in response to ~s, going from 'calling' to 'proceeding'", [Method]),
  +received_response_state_machine("INVITE", Status, calling) when Status == 100 ->
  +    logger:log(debug, "UAC decision: Received 100 in response to INVITE, going from 'calling' to 'proceeding'"),
       {ignore, proceeding};
  -received_response_state_machine(Method, Status, State) when Status == 100 ->
  -    logger:log(debug, "UAC decision: Received 100 in response to ~s when in state '~p', ignoring", [Method, State]),
  +received_response_state_machine(Method, Status, trying) when Status == 100 ->
  +    logger:log(debug, "UAC decision: Received 100 in response to ~s, going from 'trying' to 'proceeding'", [Method]),
  +    {ignore, proceeding};
  +received_response_state_machine("INVITE", Status, State) when Status == 100 ->
  +    logger:log(debug, "UAC decision: Received 100 in response to INVITE when in state '~p', ignoring", [State]),
       {ignore, State};
   
   
  
positive.code: 
  %%--------------------------------------------------------------------
  %% External exports
  -export([start/6]).
  
  %% gen_server callbacks
  -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
  
negative.code:     {URI, Header} = {Request#request.uri, Request#request.header},
      RHeader = Response#response.header,
      LogTag = State#state.logtag,
      logger:log(debug, "~s: Sending ACK of '~p ~s' in response to ~s ~s",
  	       [LogTag, Status, Response#response.reason, Request#request.method, sipurl:print(URI)]),
      {CSeq, _} = sipheader:cseq(Header),
      %% Don't copy any Via headers. send_proxy_request() will add one for this proxy,
      %% and that is the only one that should be in an ACK. RFC 3261 17.1.1.3
      %% copy() To and then set() it to preserve order...
  