return stats if no pkgs avail

rtt.go

@@ -122,6 +122,11 @@ func (cp *ContinuousPinger) Stats(dSent, dReceive int) (*PingStats, error) {
 			pkgsInArr++
 		}
 	}
+
+	if pkgsInArr == 0 {
+		return ps, nil
+	}
+
 	ps.AvgRtt = time.Duration(sum / int64(pkgsInArr))
 	ps.PacketLoss = math.Min(100, math.Max(100-(float64(dReceive)/float64(dSent)*100), 0))
 	if math.IsNaN(ps.PacketLoss) || math.IsInf(ps.PacketLoss, 0) {