dotnet httpclient请求指定content-typ

var httpClient = new HttpClient();
var content = new StringContent("id=foo&name=bar", Encoding.UTF8, "application/x-www-form-urlencoded");
// var content = new StringContent("<xml><foo></foo></xml>", Encoding.UTF8, "application/xml");
var result = httpClient.PostAsync("http://localhost", content).ConfigureAwait(false).GetAwaiter().GetResult();
var responseString = result.Content.ReadAsStringAsync().ConfigureAwait(false).GetAwaiter().GetResult();