anchor.diff:  
   function TMARSWebRequest.GetHeaderParamValue(const AHeaderName: string): string;
   begin
  -  if FWebRequest is TMARSIdHTTPAppRequest then
  +  if (FWebRequest is TMARSIdHTTPAppRequest) or (FWebRequest is TIdHTTPAppRequest) then
       Result := TMARSIdHTTPAppRequest(FWebRequest).RequestInfo.RawHeaders.Values[AHeaderName]
     else
       Result := FWebRequest.GetFieldByName(AHeaderName);
  
positive.code: 
  function TMARSWebRequest.GetHeaderParamCount: Integer;
  begin
    if FWebRequest is TMARSIdHTTPAppRequest then
      Result := TMARSIdHTTPAppRequest(FWebRequest).RequestInfo.RawHeaders.Count
    else
      raise EMARSEngineException.Create('[Indy] Not supported: GetHeaderParamCount by Index');
  
negative.code: 
  function TMARSWebRequest.GetHeaderParamIndex(const AName: string): Integer;
  begin
    if (FWebRequest is TMARSIdHTTPAppRequest) or (FWebRequest is TIdHTTPAppRequest) then
      Result := TMARSIdHTTPAppRequest(FWebRequest).RequestInfo.RawHeaders.IndexOfName(AName)
    else
      raise EMARSEngineException.Create('[Indy] Not supported: GetHeaderParamIndex by Index');
  