问必须显式关闭异步http请求的ResponseStream吗？

EN

// the request state class, passed along with async request
public class RequestState
{             
    public HttpWebRequest Request { get; set; }
    public HttpWebResponse Response { get; set; }

    // some other properties to track which request this is..
}

...... in some other class .....

// code to perform the request
public void DoHttpRequest() 
{
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://myurl.....");
    RequestState state = new RequestState(req); // this just sets the Request property on RequestState
    req.BeginGetResponse(OnRequestComplete, state);
}

// the callback, request has finished
public void OnRequestComplete(IAsyncResult result)
{
    RequestState state = (RequestState)result.AsyncState;
    HttpWebRequest req = state.Request;
    state.Response = (HttpWebResponse)req.EndGetResponse(result);

    // we do not care about the body of the response
    // all we want is the status code, which we store somewhere else..

    if (state.Response.StatusCode == HttpStatusCode.OK || state.Response.StatusCode == HttpStatusCode.Created)
    {
         // comm was successful
         // save this result code somewhere...
    }
    else if (state.Response.StatusCode == HttpStatusCode.RequestTimeout || state.Response.StatusCode == HttpStatusCode.GatewayTimeout)
    {
          // comm timed out
          // save this result code somewhere..
    }
    else
    {
          // something else, comm failed
          // save this result code somewhere..
    }

    // we've got the relevant data from the HttpWebResponse object, dispose of it
    state.Response.Close();
}