Bash process substitution and syncing

Question

(Possibly related to Do some programs not accept process substitution for input files?)

In some Bash unit test scripts I\'m using the following trick to log and<

Answer 1

I sometimes put a guard:

: > >(sleep 1; echo a; touch guard) \
  && while true; do
    [ -f "guard" ] && { rm guard; break; }
     sleep 0.2
  done