public async Task <FileContentResult> Post()
        {
            using var reader = new StreamReader(Request.Body);
            var requestBody = await reader.ReadToEndAsync();

            reader.Close();

            if (requestBody.Length < 23)
            {
                return(new FileContentResult(new byte[] {}, "text/plain"));
            }

            var imageBase64 = RemoveDataUrlPrefix(requestBody);
            var imageBytes  = Convert.FromBase64String(imageBase64);

            await using var ms = new MemoryStream(imageBytes, 0, imageBytes.Length);
            _imageProcessor.SetImage(ms);
            var qrCodeMontage = _imageProcessor.GenerateMontage();

            return(File(qrCodeMontage.ToByteArray(MagickFormat.Png), "image/png"));
        }