System.Net.Http.HttpClient.PostAsync C# (CSharp) Method

        public Task<HttpResponseMessage> PostAsync(Uri requestUri, HttpContent content)
        {
            return PostAsync(requestUri, content, CancellationToken.None);
        }

 public async Task<Result> PostData(Uri uri, MultipartContent header, StringContent content)
 {
     var httpClient = new HttpClient();
     try
     {
         if (!string.IsNullOrEmpty(AuthenticationToken))
         {
             httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", AuthenticationToken);
         }
         HttpResponseMessage response;
         if (header == null)
         {
             if(content == null) content = new StringContent(string.Empty);
             response = await httpClient.PostAsync(uri, content);
         }
         else
         {
             response = await httpClient.PostAsync(uri, header);
         }
         var responseContent = await response.Content.ReadAsStringAsync();
         return new Result(response.IsSuccessStatusCode, responseContent);
     }
     catch (Exception ex)
     {
         throw new WebException("Kinder Chat API Error: Service error", ex);
     }
 }