Origin: http://www.zsh.org/mla/workers/2014/msg01250.html
Author: Bart Schaefer <schaefer@brasslantern.com>
Bug-Debian: https://bugs.debian.org/759870
Description: Add a sleep call which should prevent a race condition in coproc

Index: zsh/Test/A05execution.ztst
===================================================================
--- zsh.orig/Test/A05execution.ztst	2015-08-30 22:03:54.257198175 +0200
+++ zsh/Test/A05execution.ztst	2015-08-30 22:03:54.257198175 +0200
@@ -208,6 +208,7 @@
   print -u $ZTST_fd 'This test takes 5 seconds to fail...'
   { printf "%d\n" {1..20000} } 2>/dev/null | ( read -e )
   hang(){ printf "%d\n" {2..20000} | cat }; hang 2>/dev/null | ( read -e )
+  sleep 1 ;: avoid coproc exit race condition
   print -p done
   read -et 6 -p
 0:Bug regression: piping a shell construct to an external process may hang