Since this project has forked logic of upstream 'archive/tar', this does
a brief comparison including the RawBytes usage.
```bash
$ go test -run="XXX" -bench=.
testing: warning: no tests to run
BenchmarkUpstreamTar-4 2000 700809 ns/op
BenchmarkOurTarNoAccounting-4 2000 692055 ns/op
BenchmarkOurTarYesAccounting-4 2000 723184 ns/op
PASS
ok vb/tar-split 4.461s
```
From this, the difference is negligible.
Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
