Rx UNIX_EPOCH timestamps add the epoch offset once per hardware packet #381

In TRXLooper::ReceivePacketsLoop the user packet's timestamp is initialized once per DMA buffer, but the epoch correction sits inside the per-sub-packet loop:

for (int i = 0; i < srcPktCount; ++i)
{
    ...
    if (mConfig.timestampType == TimestampType::UNIX_EPOCH)
    {
        userPkt->meta.timestamp = userPkt->meta.timestamp + Timespec(startUnixTime);
        userPkt->meta.timestamp = userPkt->meta.timestamp - fpgaFrontEndDelay;
    }
}

One user packet aggregates packetsToBatch hardware packets (3 at 30.72 Msps with the default heuristic), so the delivered timestamp becomes hwts + N*startUnixTime - N*delay. With startUnixTime around 1.75e9 seconds the reported Rx time is billions of seconds in the future.