帮忙分析下这段下载代码

// 输出硬盘文件，提供下载 

// 输入参数 _Request: Page.Request对象， _Response: Page.Response对象， _fileName: 下载文件名， _fullPath: 带文件名下载路径， _speed 每秒允许下载的字节数 

// 返回是否成功 

public static bool ResponseFile(HttpRequest _Request,HttpResponse _Response,string _fileName,string _fullPath, long _speed) 

{ 

	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; 



			int pack = 10240; //10K bytes 

			//int sleep = 200; //每秒5次 即5*10K bytes每秒 

			int sleep = (int)Math.Floor((double)(1000 * pack / _speed)) + 1; 

			if (_Request.Headers["Range"] != null) 

			{ 

				_Response.StatusCode = 206; 

				string[] range = _Request.Headers["Range"].Split(new char[] {'=', '-'}); 

				startBytes = Convert.ToInt64(range[1]); 

			} 

			_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(_fileName,System.Text.Encoding.UTF8) ); 



			br.BaseStream.Seek(startBytes, SeekOrigin.Begin); 

			int maxCount = (int) Math.Floor((double)((fileLength - startBytes) / pack)) + 1; 



			for (int i = 0; i < maxCount; i++) 

			{ 

				if (_Response.IsClientConnected) 

				{ 

					_Response.BinaryWrite(br.ReadBytes(pack)); 

					System.Threading.Thread.Sleep(sleep); 

				} 

				else 

				{ 

					i=maxCount; 

				} 

			} 

		} 

		catch 

		{ 

			return false; 

		} 

		finally 

		{ 

			br.Close(); 

			myFile.Close(); 

		} 

	} 

	catch(System.Exception e)

	{ 

		string s = e.ToString();

		return false; 

	} 

	return true; 

}