FSClient.ContactPluginManager.calls_CollectionChanged C# (CSharp) Method

        private void calls_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            //We want to background resolve things incase a plugin does something that takes awhile
            if (e.NewItems == null || active_plugin == null)
                return;
            bgresolve_worker_init();
            lock (pending_bg_queue.SyncRoot) {
                foreach (Call c in e.NewItems) {
                    if (bgResolveWorker.IsBusy || pending_bg_queue.Count > 0)
                        pending_bg_queue.Enqueue(c);
                    else
                        bgResolveWorker.RunWorkerAsync(c);
                }

            }
        }