Use bytes instead of strings, and slice in-place filter
(see https://github.com/golang/go/wiki/SliceTricks#filter-in-place)
to avoid copying strings around.
In my benchmark it shows almost 2x improvement:
BenchmarkString-8 1477207 10198 ns/op
BenchmarkBuffer-8 1561291 7622 ns/op
BenchmarkInPlace-8 2295714 5202 ns/op
String is the original implementation, Buffer is an intermediary
one that uses strings.Builder, and InPlace is the one from this commit.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
78e98da1db