use strict;
use warnings;
use Data::Dumper;
use MCE;
use Time::HiRes 'sleep';

my %res = ();
my $mce = MCE->new(
    max_workers => 5,
    posix_exit  => 1,
    gather      => \%res,
);

my @input = 1..10;

$mce->foreach(\@input, sub {
  # my ($mce, $chunk_ref, $chunk_id) = @_;
  # my $item = $chunk_ref->[0];   # or $_
    my $item = $_;

    MCE->printf("Worker %s began item $item\n", MCE->wid);
    sleep 0.01; # simulate work
    MCE->gather($item => $item * 2);

    MCE->printf("Worker %s ended item $item\n", MCE->wid);
});

$mce->shutdown;

print Dumper(\%res);