await RefreshMembershipIfNewer(address.MembershipVersion);

            // see if the owner is somewhere else (returns null if we are owner)
            var forwardAddress = this.CheckIfShouldForward(address.GrainId, hopCount, "UnregisterAsync");

            // After the first forward, we insert a retry delay and recheck owner before forwarding again
            if (hopCount > 1 && forwardAddress != null)
            {
                await Task.Delay(RETRY_DELAY);
                forwardAddress = this.CheckIfShouldForward(address.GrainId, hopCount, "UnregisterAsync");

            var previousSnapshot = this.clusterMembershipService.CurrentSnapshot;

            ((ITestAccessor)this).LastMembershipVersion = previousSnapshot.Version;

            var updates = this.clusterMembershipService.MembershipUpdates.WithCancellation(this.shutdownToken.Token);
            await foreach (var snapshot in updates)
            {
                // Active filtering: detect dead silos and try to clean proactively the directory
                var changes = snapshot.CreateUpdate(previousSnapshot).Changes;
                var deadSilos = changes
                    .Where(member => member.Status == SiloStatus.Dead)
                    .Select(member => member.SiloAddress)
                    .ToList();

                if (deadSilos.Count > 0)
                {
                    var tasks = new List<Task>();
                    foreach (var directory in this.grainDirectoryResolver.Directories)
                    {
                        tasks.Add(directory.UnregisterSilos(deadSilos));
                    }
                    await Task.WhenAll(tasks).WaitAsync(this.shutdownToken.Token);
                }

                ((ITestAccessor)this).LastMembershipVersion = snapshot.Version;
            }