Making it completely Perl 5 compatible?

I'm considering porting Perl 5's `Benchmark` completely, which would mean a slightly different API.

I see two ways of doing this
- take this repo and add all functionality needed, returning a `Map` with a `method sink` mixed-in that would `say` the output.  So that it would match Perl 5's use of e.g. `timethese` in void context.
- start a new repo and work from scratch.

Opinions?