~/.cpan/build/AnyEvent-ForkManager-0.04-ZOUXbL$ ./Build test
t/000_load.t ...... 1/1 # Testing AnyEvent::ForkManager/0.04
t/000_load.t ...... ok
t/001_basic.t ..... 1/63

##</code><code>##

    $pm->start(
        cb => sub {
            my($pm, $exit_code) = @_;
            local $SIG{USR1} = sub { $started_all_process = 1; };
            isnt $$, $pm->manager_pid, 'called by child';       # <<== HERE
            until ($started_all_process) {}; # wait
            note "exit_code: $exit_code";
            $pm->finish($exit_code);
            fail 'finish failed';
        },
        args => [$exit_code]
    );

##</code><code>##

my $mpid = $pm->manager_pid;
isnt $$, $mpid, 'called by child';

##</code><code>##

sub new {
    my ($class, $store) = @_;

    $store->_reopen_if_needed;

    if ($store->{lock}++ == 0) {
        flock $store->{fh}, LOCK_EX or die $!;  # <<== HERE
    }

    bless { store => $store }, $class;
}

##</code><code>##

use Data::Dumper; $Data::Dumper::Deparse = 1; warn Dumper($store);

##</code><code>##

use Time::HiRes qw{ usleep }; usleep 200;