anchor.diff:  function TFhirHTTPClient.exchange(url : String; verb : TFhirHTTPClientHTTPVerb; source : TStream; ct : String = '') : TStream;
   begin
     createClient;
  +  LastURL := url;
     if FUseIndy then
       result := exchangeIndy(url, verb, source, ct)
     {$IFDEF MSWINDOWS}
  
positive.code:   end;
  
    TFhirClient = {abstract} class (TAdvObject)
    public
      function link : TFhirClient; overload;
  
  
negative.code:     procedure terminate; virtual;
      function address : String; virtual;
      function format : TFHIRFormat; virtual;
      property LastURL : String read FLastURL write FLastURL;
    end;
  
    TFhirHTTPClientHTTPVerb = (get, post, put, delete, options, patch);
  