msdn 中snmp 的例子，基于控制台程序实现。实现了 get/getnext/set/walk/trap 等，阅读 readme 就可以更加明白，现在这个例子不好找了，故整理之。-msdn in snmp example, based on the console program. Realize the get/getnext/set/walk/trap, etc., read the readme to be more awar