miekg/dns — pull request #82 by millerkil (2014-01-31 19:55:43+00:00)
Title: Use slice to build domain string for unpacking

Considerably faster than simply using string concatenation. A lot more memory efficient too.

```
BenchmarkMsgUnpack	50000	57474 ns/op	16730 B/op	674 allocs/op
```

```
BenchmarkMsgUnpack	500000	7247 ns/op	813 B/op	23 allocs/op
```

I also added a benchmark to monitor domain unpacking performance in the future.