Reassembler perfomance improvement

[dselyuzhitskiy]

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:

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?