procedure TForm1.SpeedButton1Click(Sender: TObject);
var List:TStringList;
    Stream:TMemoryStream;
begin
   List := TStringList.Create;
   Stream:= TMemoryStream.Create;
//   ----  Код  ---------
   List.SaveToStream(Stream);
   IdTCPClient1.IOHandler.WriteLn(IntToStr(Stream.Size));
   IdTCPClient1.IOHandler.Write(Stream);
   List.Free;
   Stream.Free;
end;