Log larga negative gap. (#2138)

Seeing a large positive gap which I am not able to explain.
Wondering if at some other time, a large negative is happening
and the large positive is just a correction.

pkg/sfu/buffer/rtpstats_receiver.go

@@ -150,6 +150,9 @@ func (r *RTPStatsReceiver) Update(
 				return
 			}
 		}
+		if gapSN <= cNumSequenceNumbers {
+			r.logger.Warnw("large sequence number gap negative", nil, "prev", resSN.PreExtendedHighest, "curr", resSN.ExtendedVal, "gap", gapSN)
+		}
 
 		if gapSN != 0 {
 			r.packetsOutOfOrder++

pkg/sfu/buffer/rtpstats_sender.go

@@ -281,6 +281,9 @@ func (r *RTPStatsSender) Update(
 			// do not start on a padding only packet
 			return
 		}
+		if gapSN <= cNumSequenceNumbers {
+			r.logger.Warnw("large sequence number gap negative", nil, "prev", r.extHighestSN, "curr", extSequenceNumber, "gap", gapSN)
+		}
 
 		if extSequenceNumber < r.extStartSN {
 			r.packetsLost += r.extStartSN - extSequenceNumber