# ><[0]
echo Ok | { sleep 0.1; read -t 0 reply; echo ">$reply<[$?]"; }

# This would not be deterministic: returns 0 "data exists" if EOF is seen
# (true terminated) - because EOF is considered to be data (read will not block),
# else returns 1 "no data".
## ><[????]
#true | { read -t 0 reply; echo ">$reply<[$?]"; }

# ><[0]
true | { sleep 0.1; read -t 0 reply; echo ">$reply<[$?]"; }

# ><[1]
sleep 0.2 | { read -p IGNORED_PROMPT -t 0 reply; echo ">$reply<[$?]"; }