private void Handle(ClusterActorDiscoveryMessage.RegisterCluster m)
        {
            _log.Info($"RegisterCluster: {m.ClusterAddress}");

            // Register node

            var item = _nodeMap.FirstOrDefault(i => i.Value.ClusterAddress == m.ClusterAddress);

            if (item.Key != null)
            {
                _log.Error($"Already registered node. {m.ClusterAddress}");
                return;
            }

            _nodeMap.Add(Sender, new NodeItem
            {
                ClusterAddress = m.ClusterAddress,
                ActorItems     = new List <ActorItem>()
            });

            // Process attached actorUp messages

            if (m.ActorUpList != null)
            {
                foreach (var actorUp in m.ActorUpList)
                {
                    Handle(actorUp);
                }
            }
        }