/// <summary>
 /// 从系统中获取两个不被占用的端口号
 /// </summary>
 /// <returns></returns>
 public static IEnumerable <int> SetMediaPort()
 {
     lock (PortLock)
     {
         return(Enumerable.Range(UdpPortStart, UdpPortEnd).Except(GetUsedUdpPorts.ToList()).Take(2));
     }
 }
 /// <summary>
 /// 检查端口号是否被专用
 /// </summary>
 /// <param name="port">端口号</param>
 /// <returns>true,被占用,false没被占用</returns>
 public static bool CheckUdpPort(int port)
 {
     return(!GetUsedUdpPorts.Contains(port));
 }