httpclient请求

var Client = new HttpClient();

Client.DefaultRequestHeaders.Clear();

Client.DefaultRequestHeaders.Add("Header1", "Value1");

Client.DefaultRequestHeaders.Add("Header2", "Value2");

Client.DefaultRequestHeaders.Add("Header3", "Value for exact this request");

var response = Client.PutAsync(new Uri($"http://example.com/books/1234/readers/837"), null); //.Result (?)

Client.Dispose();