Opc.Ua.ServerTest.SubscribeTest.DeleteSubscriptions C# (CSharp) Method

        private bool DeleteSubscriptions()
        {   
            try
            {
                UInt32Collection subscriptionIds = new UInt32Collection();

                lock (m_subscriptions)
                {
                    for (int ii = 0; ii < m_subscriptions.Count; ii++)
                    {
                        Subscription subscription = m_subscriptions[ii];

                        lock (subscription)
                        {
                            subscriptionIds.Add(subscription.SubscriptionId);
                            subscription.Deleted = true;
                        }
                    }
                }
                    
                RequestHeader requestHeader = new RequestHeader();
                requestHeader.ReturnDiagnostics = 0;

                StatusCodeCollection results;
                DiagnosticInfoCollection diagnosticInfos;

                ResponseHeader responseHeader = Session.DeleteSubscriptions(
                    requestHeader,
                    subscriptionIds,
                    out results,
                    out diagnosticInfos);

                ClientBase.ValidateResponse(results, subscriptionIds);
                ClientBase.ValidateDiagnosticInfos(diagnosticInfos, subscriptionIds);
                                
                if (diagnosticInfos != null && diagnosticInfos.Count > 0)
                {
                    Log("Returned non-empty DiagnosticInfos array during DeleteSubscriptions.");
                    return false;
                }

                bool success = true;

                lock (m_subscriptions)
                {
                    for (int ii = 0; ii < m_subscriptions.Count; ii++)
                    {
                        if (StatusCode.IsBad(results[ii]))
                        {
                            Log(
                                "Unexpected error deleting subscription {0}. StatusCode = {1}",
                                subscriptionIds[ii],
                                subscriptionIds);

                            success = false;
                        }

                        Subscription subscription = m_subscriptions[ii];

                        lock (subscription)
                        {
                            subscription.States[subscription.States.Count - 1].End = responseHeader.Timestamp;
                        }
                    }
                }

                // let the queue empty.
                Thread.Sleep(1000);

                return success;
            }
            catch (Exception e)
            {
                Log(e, "DeleteSubscriptions Failed.");
                return false;
            } 
        }