anchor.diff:      Contact = {'contact', ContactValue},
   
       % configure pre-existing route set
  -    Routes = [{'route', sip_headers:route(Route, [])} || Route <- sip_config:routes()],
  +    Routes = [{'route', sip_headers:address(<<>>, sip_uri:parse(RouteBin), [])} || RouteBin <- sip_config:routes()],
   
       #sip_message{kind = #sip_request{method = Method, uri = RequestURI},
                    headers = [Via, MaxForwards, From, To, CSeq, CallId, Contact] ++ Routes}.
  
positive.code: handle_response(_UserData, _Msg, State) ->
      {noreply, State}.
  
  -spec is_applicable(#sip_message{}) -> boolean().
  is_applicable(_Msg) -> false.
  
  %%-----------------------------------------------------------------
  %% Internal functions
  %%-----------------------------------------------------------------
  
negative.code:             {error, not_found} ->
                  RequestURI;
              {ok, #sip_hdr_address{uri = Route}} ->
                  % See RFC3261, 8.1.2
                  % If first element in the route set is strict router,
                  % use Request-URI
                  case is_strict_router(Route) of
                      true -> RequestURI;
                      false -> Route
                  end
  