Opc.Ua.Client.Session.BeginPublish C# (CSharp) Method

        public IAsyncResult BeginPublish(int timeout)
        { 
            // do not publish if reconnecting.
            if (m_reconnecting)
            {
                Utils.Trace("Published skipped due to reconnect");
                return null;
            }

            SubscriptionAcknowledgementCollection acknowledgementsToSend = null;

            // collect the current set if acknowledgements.
            lock (SyncRoot)
            {
                acknowledgementsToSend = m_acknowledgementsToSend;
                m_acknowledgementsToSend = new SubscriptionAcknowledgementCollection();
                foreach (var toSend in acknowledgementsToSend)
                {
                    if (m_latestAcknowledgementsSent.ContainsKey(toSend.SubscriptionId))
                    {
                        m_latestAcknowledgementsSent[toSend.SubscriptionId] = toSend.SequenceNumber;
                    }
                    else
                    {
                        m_latestAcknowledgementsSent.Add(toSend.SubscriptionId, toSend.SequenceNumber);
                    }
                }
            }

            // send publish request.
            RequestHeader requestHeader = new RequestHeader();

            // ensure the publish request is discarded before the timeout occurs to ensure the channel is dropped.
            requestHeader.TimeoutHint       = (uint)OperationTimeout/2;
            requestHeader.ReturnDiagnostics = (uint)(int)ReturnDiagnostics;
            requestHeader.RequestHandle     = Utils.IncrementIdentifier(ref m_publishCounter);
            
            AsyncRequestState state = new AsyncRequestState();

            state.RequestTypeId = DataTypes.PublishRequest;
            state.RequestId = requestHeader.RequestHandle;
            state.Timestamp = DateTime.UtcNow;

            try
            {                
                IAsyncResult result = BeginPublish(
                    requestHeader, 
                    acknowledgementsToSend, 
                    OnPublishComplete, 
                    new object[] { SessionId, acknowledgementsToSend, requestHeader });
                    
                AsyncRequestStarted(result, requestHeader.RequestHandle, DataTypes.PublishRequest);

                // Utils.Trace("PUBLISH #{0} SENT", requestHeader.RequestHandle);

                return result;
            }
            catch (Exception e)
            {   
                Utils.Trace(e, "Unexpected error sending publish request.");
                return null;
            }
        }