client.BaseAddress = new Uri("http://xxx.xxx.xx.xx:xxxx/);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = client.GetAsync("api/xxx/xxxxxx").Result;
ResponseMessage msg = response.Content.ReadAsAsync<ResponseMessage>().Result;