Time slider with feature count

Hi,

I'm using the time slider with a time-aware dynamic map service and am trying to figure out how to get the feature count as well as all the features information as the time slider is playing. I'm trying to listen to the event LayerEvent.Update_End, it fires everytime the slider moves, but could not get the count correctly - the numGraphics always show the total number of features in the layers.

Any help pointing me to the right direction to get this is much appreciated.