配置.NET程序中最大HTTP并发连接数（默认为2）

方式一：代码

ServicePointManager.DefaultConnectionLimit = 10

方式二：配置

  <system.net>

    <connectionManagement>

      <add address = "http://www.contoso.com" maxconnection = "4" />

      <add address = "*" maxconnection = "2" />

    </connectionManagement>

  </system.net>