Flag indicating if the collection is actively tracing cache misses into cacheMissCollection.
Cache miss tracing can only begin if the current collection is used to prewarm shader variant states via WarmUp. While true, any time a shader variant permutation that does not exist in the current collection is used, it will be added to the cache miss collection. Use EndTrace with the cacheMissCollection to stop tracing. Additional resources: isTracing, WarmUp, EndTrace.