public static bool ResponseFile(HttpContext context, string _fullPath, long _speed){HttpRequest _Request = context.Request;HttpResponse _Response = context.Response;string strFileName = new FileInfo(_fullPath).Name;try{FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);BinaryReader br = new BinaryReader(myFile);try{_Response.AddHeader("Accept-Ranges", "bytes");_Response.Buffer = false;long fileLength = myFile.Length;long startBytes = 0;_Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());if (startBytes != 0){_Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength - 1, fileLength));}_Response.AddHeader("Connection", "Keep-Alive");_Response.ContentType = "application/octet-stream";_Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(strFileName, System.Text.Encoding.UTF8));int pack = 10240; //10K bytes       进行拆包,每包大小                   byte[] buff = new byte[pack];var contentLength = br.Read(buff, 0, pack);double d = 1000 / (_speed / pack); // 限速时每个包的时间Stopwatch wa = new Stopwatch();while (contentLength != 0){if (_Response.IsClientConnected){wa.Restart();_Response.BinaryWrite(buff);_Response.Flush();contentLength = br.Read(buff, 0, pack);wa.Stop();if (wa.ElapsedMilliseconds < d) //如果实际带宽小于限制时间就不需要等待
                            {Thread.Sleep((int)(d - wa.ElapsedMilliseconds));}}else{break;}}                     }catch{return false;}finally{br.Close();myFile.Close();}}catch{return false;}return true;}