private async Task UpdateTopicRoute()

in rocketmq-client-csharp/Client.cs [138:193]
45 lines of code
8 McCabe index (conditional complexity)

        private async Task UpdateTopicRoute()
        {
            HashSet<string> topics = new HashSet<string>();
            foreach (var topic in topicsOfInterest_)
            {
                topics.Add(topic);
            }

            foreach (var item in _topicRouteTable)
            {
                topics.Add(item.Key);
            }
            Logger.Debug($"Fetch topic route for {topics.Count} topics");

            // Wrap topics into list such that we can map async result to topic 
            List<string> topicList = new List<string>();
            topicList.AddRange(topics);

            List<Task<TopicRouteData>> tasks = new List<Task<TopicRouteData>>();
            foreach (var item in topicList)
            {
                tasks.Add(GetRouteFor(item, true));
            }

            // Update topic route data
            TopicRouteData[] result = await Task.WhenAll(tasks);
            var i = 0;
            foreach (var item in result)
            {
                if (null == item)
                {
                    Logger.Warn($"Failed to fetch route for {topicList[i]}, null response");
                    ++i;
                    continue;
                }

                if (0 == item.MessageQueues.Count)
                {
                    Logger.Warn($"Failed to fetch route for {topicList[i]}, empty message queue");
                    ++i;
                    continue;
                }

                var topicName = item.MessageQueues[0].Topic.Name;

                // Make assertion
                Debug.Assert(topicName.Equals(topicList[i]));

                var existing = _topicRouteTable[topicName];
                if (!existing.Equals(item))
                {
                    _topicRouteTable[topicName] = item;
                }
                ++i;
            }
        }