Phobos PR in need of review/merge

[Meta via Digitalmars-d]

On Tuesday, 27 June 2017 at 01:49:52 UTC, Meta wrote:
> Another PR that somebody in IRC mentioned: 
> https://github.com/dlang/phobos/pull/5004
>
> This one hasn't had any response for awhile either.

The first PR has been reviewed and merged thanks to Jack Stouffer 
and Wilzbach. Can anyone familiar with std.concurrency review 
this one?