public async Task<SubtractResponse> SubtractAsync(SubtractRequest request)
 {
     using (var client = new WebClient())
     {
         await client.DownloadDataTaskAsync(new Uri(this.url + "subtract?id=" + request.CalculatorId + "&value=" + request.Value));
     }
     return new SubtractResponse();
 }
 public SubtractResponse Subtract(SubtractRequest request)
 {
     using (var client = new WebClient())
     {
         client.DownloadData(new Uri(this.url + "subtract?id=" + request.CalculatorId + "&value=" + request.Value));
     }
     return new SubtractResponse();
 }