use strict;
use warnings;
use threads;
use IO::Socket::INET qw( );
use constant SHUT_WR => 1;

my $sock = IO::Socket::INET->new(
   Proto    => 'tcp',
   PeerAddr => $ARGV[0] // 'localhost:echo',
)
   or die $!;

async {
   print while <$sock>;
};

async {
   print($sock "abc\n");
   sleep(3);
   print($sock "def\n");
   shutdown($sock, SHUT_WR);
};

$_->join for threads->list;