public static Task <HttpResponseMessage> PostContentAsJsonAsync <T>(this HttpClient client, Uri requestUri, T requestContent)
 {
     return(client.PostContentAsJsonAsync(requestUri, requestContent, CancellationToken.None));
 }
 public static Task <HttpResponseMessage> PostContentAsJsonAsync <T>(this HttpClient client, string requestUrl, T requestContent, CancellationToken cancellationToken)
 {
     return(client.PostContentAsJsonAsync(new Uri(requestUrl), requestContent, cancellationToken));
 }