HttpWebRequest.GetResponse()是自动在响应完成后调用吗?该怎么处理

HttpWebRequest.GetResponse()是自动在响应完成后调用吗??
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(reqUrl);

request.GetResponse()是自动等待在响应完成后调用吗？？？还是响应还未完成就调出空的HttpWebResponse？？

C# code

string PostData = Session["QQ"] + ";00;" + num + ";" + Session["LoginKey"] + ";";HttpWebRequest request = (HttpWebRequest)WebRequest.Create(reqUrl);request.Method = "POST";byte[] bytes = Encoding.GetEncoding("GB2312").GetBytes(PostData);request.ContentType = "application/x-www-form-urlencoded";request.ContentLength = bytes.Length;     Stream sr = request.GetRequestStream();sr.Write(bytes, 0, bytes.Length);sr.Dispose();WebResponse response = request.GetResponse();