public void UnRegister(ICallConnection connection)
        {
            var toremove = new[] { connection };

            while (true)
            {
                if (!_pool.TryGetValue(connection.Namespace, out var connections))
                {
                    return;
                }

                var newconnections = connections.Except(toremove).ToArray();

                if (newconnections.Length == 0)
                {
                    if (_pool.TryRemove(connection.Namespace, out var removed))
                    {
                        foreach (var callConnection in removed.Except(toremove))
                        {
                            Register(callConnection);
                        }

                        return;
                    }

                    continue;
                }

                if (_pool.TryUpdate(connection.Namespace, newconnections, connections))
                {
                    return;
                }
            }
        }
 public void Register(ICallConnection connection)
 {
     _pool.AddOrUpdate(connection.Namespace, new[] { connection },
                       (s, connections) => connections.Concat(new[] { connection }).ToArray());
 }