RxFirstArrivalTime: Arrival time of the first packet in the filtered substream
RxLastArrivalTime: Arrival time of the last packet in the filtered substream.
These are used for multicast zapping. Not usually needed for other tests.
RxTotalLatency: Is PROBABLY the total latency for the substream.
If you divide this number by the packet count in the substream
you should get the average latency for the packets in the substream.