using System;
//using System.Collections.Generic;
//using System.Linq;
//using System.Text;
using System.Threading;
using System.Net;
namespace AsyBeginEndNoEncapsulationSimply
{
class Program
...
异步下载：
public interface IPrimaryKey<T>
{
T GetKey();
}
public class DownloadInfo : IPrimaryKey<string>
{
public string FtpResourceFilePath { get; set...
