POSIX Timers: Threaded Notification
===================================

* whole lotta code, mainly taken (and modified) from
  :doc:`../posix-async/index`
* thread notification: is a new thread created? `man -s 3 sigevent
  <https://man7.org/linux/man-pages/man3/sigevent.3type.html>`__ only
  says that it could. Performance implications?