System.Net.Sockets.SocketPal.SetMulticastOption C# (CSharp) Метод

        public static unsafe SocketError SetMulticastOption(SafeCloseSocket handle, SocketOptionName optionName, MulticastOption optionValue)
        {
            Debug.Assert(optionName == SocketOptionName.AddMembership || optionName == SocketOptionName.DropMembership, $"Unexpected optionName: {optionName}");

            Interop.Sys.MulticastOption optName = optionName == SocketOptionName.AddMembership ?
                Interop.Sys.MulticastOption.MULTICAST_ADD :
                Interop.Sys.MulticastOption.MULTICAST_DROP;

            IPAddress localAddress = optionValue.LocalAddress ?? IPAddress.Any;

            var opt = new Interop.Sys.IPv4MulticastOption {
                MulticastAddress = unchecked((uint)optionValue.Group.GetAddress()),
                LocalAddress = unchecked((uint)localAddress.GetAddress()),
                InterfaceIndex = optionValue.InterfaceIndex
            };

            Interop.Error err = Interop.Sys.SetIPv4MulticastOption(handle, optName, &opt);
            return err == Interop.Error.SUCCESS ? SocketError.Success : GetSocketErrorForErrorCode(err);
        }