public async Task<HttpResponseMessage> CallApiJsonAsync(HttpMethod method, string relativeUrl, object content)
        {
            var request = new HttpRequestMessage(method, relativeUrl);
            if (content != null)
            {
                var json = JsonConvert.SerializeObject(content);
                request.Content = new StringContent(json, Encoding.UTF8, "application/json");
            }
            return await _client.SendAsync(request);
        }

        public async Task<TResult> CallApiJsonAsync<TResult>(HttpMethod method, string relativeUrl, object content) where TResult : class
        {
            var response = await CallApiJsonAsync(method, relativeUrl, content);
            if (response.IsSuccessStatusCode)
            {
                var responseContent = await response.Content.ReadAsStringAsync();
                return JsonConvert.DeserializeObject<TResult>(responseContent);
            }
            return null;
        }