如何在使用HttpWebRequest时限制带宽的使用？

public class LimitedBandwidthWebClient : WebClient
{
    protected override WebRequest GetWebRequest(Uri address)
    {
        HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
        request.ServicePoint.ConnectionLimit = 1; // 限制并发连接数
        request.ServicePoint.MaxIdleTime = 1000; // 设置最大空闲时间
        request.ServicePoint.ConnectionLimit = 100; // 设置最大连接数
        request.ServicePoint.MaxResponseHeadersLength = 1000; // 设置最大响应头长度
        request.ServicePoint.UseNagleAlgorithm = false; // 禁用 Nagle 算法
        request.ServicePoint.Expect100Continue = false; // 禁用 Expect 100-continue
        request.ServicePoint.BindIPEndPointDelegate = new BindIPEndPoint(BindIPEndPointCallback); // 设置本地绑定 IP 地址
        return request;
    }

    private IPEndPoint BindIPEndPointCallback(ServicePoint servicePoint, IPEndPoint remoteEndPoint, int retryCount)
    {
        // 返回本地绑定的 IP 地址
        return new IPEndPoint(IPAddress.Parse("192.168.0.1"), 0);
    }
}

LimitedBandwidthWebClient client = new LimitedBandwidthWebClient();
client.DownloadData("http://example.com");