public async Task <PaymentResponse> SendAsync(PaymentRequest request, CancellationToken cancellationToken = default)
{
if (request is null)
{
throw new ArgumentNullException(nameof(request));
}
string baseUri = ApiBaseUri.Get(request.Mode);
string requestUri = $"{baseUri}/request.json";
string json = request.ToJson();
var content = new StringContent(json, Encoding.UTF8, "application/json");
using var httpClient = new HttpClient();
var response = await httpClient.PostAsync(requestUri, content, cancellationToken);
json = await response.Content.ReadAsStringAsync();
var model = JObject.Parse(json);
return(PaymentResponse(model, request.Mode));
}