D:>perl -e "$|=1;for(1..100) { sleep 1;  warn time; print time,qq{\n} }"
1530361604 at -e line 1.
1530361604
1530361605 at -e line 1.
1530361605                                # selecting text for some seconds
1530361606 at -e line 1.                  # output resumes,last buffered line 
1530361622                                # after freeze 
1530361623 at -e line 1.
1530361623
1530361624 at -e line 1.
1530361624
1530361625 at -e line 1.
1530361625
Terminating on signal SIGINT(2)