public Task<IChannel> OnTickedAsync(IPeercast peercast, IYellowPages yellowPages, string id)
        {
            return Task.Factory.StartNew(() =>
            {
                var channel = peercast.GetChannelAsync(id).Result;

                // 外部YPに通知
                if (yellowPages.IsExternal)
                {
                    ((IExternalYellowPages)yellowPages).OnTickedAsync(
                        channel.Name, channel.TotalRelays, channel.TotalListeners).Wait();
                }

                return channel;
            });
        }