Reassembler perfomance improvement

Hello!

I found, that on every new event reassembler sort sequenceNumSlice, which leads perfomance issues on high audit rate limits. I think it can be improved if make sort only if difference between new sequence and last:

```golang
l.seqs = append(l.seqs, seq)

if len(l.seqs) > 1 {
lastSeq := l.seqs[len(l.seqs)-2]

diff := abs(int64(seq) - int64(lastSeq))
if diff > maxSortRange || diff < 0 {
l.seqs.Sort()
}
}
```

What do you think about such improvement?