public async Task <IActionResult> Index(CalculateRequest req)
        {
            // Convert
            var result = await _currencyService.CalculateRate(req.FromValue, req.FromCurrencyCode, req.ToCurrnecyCode);

            // Format the Result
            ViewData["result"] = $"{req.FromValue} {req.FromCurrencyCode} = {result} {req.ToCurrnecyCode}";

            return(Index());
        }