SemiLiteEventTransformer is a special purpose ICacheEventTransformer implementation that removes an OldValue from the CacheEventArgs object for the purpose of reducing the amount of data that has to be sent over the network to event consumers.

public class SemiLiteEventTransformer : ICacheEventTransformer, 
	IPortableObject

cache.AddCacheListener(listener,
    new CacheEventTransformerFilter(null,
    SemiLiteEventTransformer.Instance), false);