Parallel.Invoke

并行调用方法或操作（并行区域）

static void Main()
{
    string [] urls = 
    {
        "www.stackoverflow.com", 
        "www.google.net", 
        "www.facebook.com", 
        "www.twitter.com"
    };
    
    System.Threading.Tasks.Parallel.Invoke(
        () => PingUrl(urls[0]),
        () => PingUrl(urls[1]),
        () => PingUrl(urls[2]),
        () => PingUrl(urls[3])
    );
}

void PingUrl(string url)
{
    var ping = new System.Net.NetworkInformation.Ping();
    
    var result = ping.Send(url);
    
    if (result.Status == System.Net.NetworkInformation.IPStatus.Success)
    {
        Console.WriteLine(string.Format("{0} is online", url));
    }
}