D3960: worker: use one pipe per posix worker and select() in parent process

[yuja (Yuya Nishihara)]

yuja added a comment.


  Queued, thanks. We'll probably need `selector.close()` somewhere.
  
  >   Do you want to move the selector import stuff to pycompat?
  
  Sounds nice. We'll have to pull the latest selectors2 module to get rid of
  reference cycle. The issue addressed by https://phab.mercurial-scm.org/rHGa568a46751b6fc87437b143582f594bfe87451f6 appears to be fixed
  in upstream.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3960

To: hooper, #hg-reviewers
Cc: yuja, mercurial-devel