traffic_replay tool generates traffic in order to measure the performance of a Samba DC. It can be used to test how well Samba will scale as the network increases in size. It can simulate multiple different hosts making multiple different types of requests to a DC, and so can be used to determine the point at which the DC becomes overloaded.
traffic_replay tool was added in Samba v4.8. Refer to its man page for more details on how to run it.
traffic_replaytool should only ever be run against a dedicated test DC. Do not run it against a live DC that is handling real network traffic.