private async Task PruneExpiredMessagesAsync(IRealm realm, CancellationToken stoppingToken)
        {
            var clientIds = realm.GetClientIdsWithQueue();

            var now     = DateTime.UtcNow;
            var maxDiff = TimeSpan.FromSeconds(10);

            var seenMap = new Dictionary <string, bool>();

            foreach (var clientId in clientIds)
            {
                var messageQueue = realm.GetMessageQueueById(clientId);

                if (messageQueue == null)
                {
                    continue;
                }

                var lastReadDiff = now - messageQueue.GetReadTimestamp();

                if (lastReadDiff < maxDiff)
                {
                    continue;
                }

                var messages = messageQueue.GetAll();

                foreach (var message in messages)
                {
                    var seenKey = $"{message.Source}_{message.Destination};";

                    if (!seenMap.TryGetValue(seenKey, out var seen) || !seen)
                    {
                        var sourceClient = realm.GetClient(message.Source);

                        await realm.HandleMessageAsync(sourceClient, Message.Create(MessageType.Expire, string.Empty), stoppingToken);

                        seenMap[seenKey] = true;
                    }
                }

                realm.ClearMessageQueue(clientId);
            }

            _logger.LogInformation($"Pruned expired messages for {seenMap.Keys.Count} peers.");
        }