my $index = $#noreply +1;
push @noreply, $obj = HTTP_Request->new($ip, $packet, sub {
    delete $noreply[$index]; 
    ..............
});

..............
..............

my $check_time = time();
my $timeout = 30;

while (1) {
    $poll->poll(5);
    for my $sock ( $poll->handles( POLLHUP | POLLERR | POLLNVAL )) {
        $sock->error();
    }

    for my $sock ( $poll->handles(POLLIN) ) {
        $sock->recv();
    }
    
    for my $sock ($poll->handles(POLLOUT)) {
        $sock->send();
    }
    
    if (time > ($check_time + $timeout)) {
        $check_time = time;
        my $i;
        foreach (@noreply) {
            if ($_ && $_->ttl < $check_time) {
                delete $noreply[$i];
                $_->close;
            }
            ++$i;
        }
    }
}
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If you willing to switch to AnyEvent, then AnyEvent::Handle allows you to set inactivity timeouts for reading and writing just as you want.

Also, calling delete on array values is deprecated. I'd suggest something like:

@noreply = grep { $_ && $_->ttl >= $check_time } @noreply;
[download]