Utility for batching ArrayCollection's ADD event. For performance optimization

CollectionEventBatcher.as

package com.zevg.utilities
{
	import flash.utils.Dictionary;
	
	import mx.collections.ListCollectionView;
	import mx.core.EventPriority;
	import mx.events.CollectionEvent;
	import mx.events.CollectionEventKind;

	public class CollectionEventBatcher
	{
		private static var collection2batchEvent:Dictionary = new Dictionary(true);
		
		/**
		 * Batching add events. For performance purpose, problem is here https://bugs.adobe.com/jira/browse/SDK-30008
		 * 
		 * IMPORTANT: Method batches only ADD events.
		 */
		public static function start(collection:ListCollectionView):void
		{
			collection.addEventListener(
				CollectionEvent.COLLECTION_CHANGE, 
				batching_collectionChangeHandler, 
				false, EventPriority.CURSOR_MANAGEMENT, true
			);
		}
		
		
		public static function stop(collection:ListCollectionView):void
		{
			collection.removeEventListener(
				CollectionEvent.COLLECTION_CHANGE, 
				batching_collectionChangeHandler
			);
			
			if (collection2batchEvent[collection])
			{
				collection.dispatchEvent(collection2batchEvent[collection]);
				delete collection2batchEvent[collection];
			}
		}
		
		private static function batching_collectionChangeHandler(event:CollectionEvent):void
		{
			// handle only ADD events
			if (event.kind != CollectionEventKind.ADD)
				return;
			
			var collection:ListCollectionView = event.target as ListCollectionView;
			
			var batchAddEvent:CollectionEvent;
			if (!collection2batchEvent[collection])
				collection2batchEvent[collection] = new CollectionEvent(CollectionEvent.COLLECTION_CHANGE, false, false, CollectionEventKind.ADD);
			
			batchAddEvent = collection2batchEvent[collection]; 
			
			batchAddEvent.items = batchAddEvent.items.concat(event.items);
			
			// swallow this event
			event.stopImmediatePropagation();
		}
	}
}

Here is use case:

var collection:ArrayCollection = new ArrayCollection;

CollectionEventBatcher.start(collection);
for each (var item:* in hugeCollectionInScope)
{
    collection.addItem(item);
}
CollectionEventBatcher.stop(collection);