anchor.diff:                       "Min-Expires: 213\r\nMIME-Version: 1.0\r\n",
                        "Organization: Boxes by Bob\r\nPriority: non-urgent\r\n",
                        "Proxy-Authenticate: Digest realm=\"atlanta.com\"\r\nProxy-Authorization: Digest username=\"Alice\"\r\n",
  -                     "Proxy-Require: foo\r\n"
  +                     "Proxy-Require: foo\r\nRecord-Route: <sip:server10.biloxi.com;lr>\r\n",
   
                        "Content-Length: 5\r\nVia: SIP/2.0/UDP localhost\r\n",
                        "To: sip:bob@localhost\r\n"
  
positive.code: process(f, 'proxy-require', Bin) ->
      sip_binary:any_to_binary(Bin);
  
  %% .....
  process(pn, <<"v">>, _Ignore) -> 'via';
  process(fn, 'via', _Ignore) -> <<"Via">>;
  
negative.code:      % Proxy-Require
       ?_assertEqual([foo, bar], parse('proxy-require', <<"foo, bar">>)),
       ?_assertEqual(<<"foo, bar">>, format('proxy-require', [foo, bar])),
  
       % Record-Route
       ?_assertEqual([address(<<>>, <<"sip:p1.example.com;lr">>, [])],
                     parse('record-route', <<"<sip:p1.example.com;lr>">>)),
       ?_assertEqual(<<"<sip:p1.example.com;lr>">>,
                     format('record-route', address(<<>>, <<"sip:p1.example.com;lr">>, []))),
  
  
  
  