主题：基础连接已经关闭: 连接被意外关闭

接口返回的数据已解析成功，但是根据返回的路径去下载附件时，就报错了

 public string HttpDownloadFile(string url, string path)
{
// 创建HttpWebRequest对象
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
//获取WebResponse对象
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
//直到request.GetResponse()程序才开始向目标网页发送Post请求
//关键：获取Stream对象 (http请求的文件流对象)
Stream responseStream = response.GetResponseStream();
//创建本地文件写入流
Stream stream = new FileStream(path, FileMode.Create);
//分段写入本地文件
byte[] bArr = new byte[1024];
int size = responseStream.Read(bArr, 0, (int)bArr.Length);
while (size > 0)
{
stream.Write(bArr, 0, size);
size = responseStream.Read(bArr, 0, (int)bArr.Length);
}
stream.Close();
responseStream.Close();
return path;
}