use strict;
use warnings;

use threads;
use Thread::Queue;

use Time::HiRes qw(time) ;
my $START = time() ;

my @t = () ;

push @t, [time(), "main thread start"] ;

my $s_q = Thread::Queue->new ;
async { $s_q->enqueue(time()) ;
        $_ = <STDIN> ;
        $s_q->enqueue(time()) ;
      }->detach() ;

if (@ARGV) {          # option to close STDIN
  close STDIN ;
  push @t, [time(), "closed STDIN"] ;
} ;

threads->yield() ;    # make sure STDIN thread starts

push @t, [time(), "about to start child thread"] ;

my $c_q = Thread::Queue->new ;
async { $c_q->enqueue(time()) ; }->detach() ;

threads->yield() ;    # make sure child thread starts

push @t, [time(), "about to collect results"] ;

push @t, [$s_q->dequeue(), "STDIN thread started"] ;
push @t, [$s_q->dequeue(), "STDIN thread received input"] ;
push @t, [$c_q->dequeue(), "child thread ran"] ;

threads->yield() ;    # give threads opportunity to complete

push @t, [time(), "main thread completes"] ;

foreach my $t (sort { $a->[0] <=> $b->[0] } @t) {
  printf "@ %9.6f: %s\n", $t->[0] - $START, $t->[1] ;
} ;