###########
use strict;
use IO::Socket;

my $Unix;
if ($^O =~ m/unix|linux|sunos|solaris|freebsd|aix/i) { $Unix = 1 }
else { $Unix = 0 }

my $sock = new IO::Socket::INET (
    LocalPort => '8181',
    Proto => 'tcp',
    Listen => SOMAXCONN,
    ReuseAddr => $Unix, 
);
die "Could not create socket: $!\n" unless $sock;
$| = 1;

my $client = $sock->accept();
print "Message1\n";
print $client "Message1\n";
# You can release client here. if not - later it will be blocked.
#close($client);

# Something that wastes time + separate process creator
my $cmd;
if ($Unix) {
    $cmd = 'pause 10';
    $cmd .= ' &';
}
else {
    $cmd = 'pause';
    $cmd = 'cmd.exe /c start cmd.exe /c ' . $cmd;
}
# This will block both Unix and Win clients if the server is on Win
system($cmd);
close($client);
$sock->shutdown(2);
close($sock);