How to debug a script that will kill by system when await multi Promise?

Answer "the script used too much memory".

I start a few start to read text file line by line, and convert the text to blob, then send it to socket:

    use experimental :pack;

    sub heart-msg(Str $msg, Str $device-id --> Blob) {
        my $heart-msg = $msg.substr(0, $msg.chars - 8);
        my $header-buf = pack("H*", $heart-msg);
        my $device-id-buf = pack("L*", $device-id);

        $header-buf ~ $device-id-buf
    }

    sub deal-message(Str $msg, Str $device-id --> Blob) {
        my $now    = DateTime.now();
        my $year   = $now.year;
        my $month  = $now.month;
        my $day    = $now.day;
        my $hour   = $now.hour;
        my $minute = $now.minute;
        my $second = $now.second.Int;
        my $check-number = 0;

        my $head-msg         = $msg.substr(0,4);
        my $device-id-length = $msg.substr(4,2);
        my $pf-code          = $msg.substr(14, 2);
        my $msg-length       = $msg.substr(16, 4);
        my $rel-time         = $msg.substr(20, 4);
        my $end-msg          = $msg.substr(38, $msg.chars - 38 - 2);

        my $head-msg-buf      = pack("H*", $head-msg);
        my $device-id-len-buf = pack("H*", $device-id-length);
        my $device-id-buf     = pack("L*", $device-id);
        my $pf-code-buf       = pack("H*", $pf-code);
        my $msg-length-buf    = pack("H*", $msg-length);
        my $rel-time-buf      = pack("H*", $rel-time);
        my $year-buf          = pack("S*", $year);
        my $month-buf         = pack("C*", $month);
        my $day-buf           = pack("C*", $day);
        my $hour-buf          = pack("C*", $hour);
        my $minute-buf        = pack("C*", $minute);
        my $second-buf        = pack("C*", $second);
        my $end-msg-buf       = pack("H*", $end-msg);

        my @bufs = [$device-id-len-buf, $device-id-buf, $pf-code-buf, $msg-length-buf,
        $rel-time-buf, $year-buf, $month-buf, $day-buf, $hour-buf, $minute-buf, $second-buf,
        $end-msg-buf];

        for @bufs -> $byte {
            my $byte_sum = [+] $byte.contents;
            $check-number += $byte_sum;
        }

        $check-number = $check-number % 256;
        my $checked-msg-buf = pack("C*", $check-number);

        [~] $head-msg-buf, |@bufs, $checked-msg-buf
    }


    sub deal-data(Str $msg, Str $device-id --> Blob) {
        my $header = $msg.substr(0, 4);
        given $header {
            when '6868' {
                return deal-message($msg, $device-id);
            }
            when '7468' {
                return heart-msg($msg, $device-id);
            }
            default { return Buf.new }
        }
    }


sub MAIN(
         :$host = '10.0.0.77',
         Int() :$port = 4444,
         Rat() :$interval = 0.001,
         :$file = 'data.txt',
         Int() :$device-num = 169) {
    my $conn = IO::Socket::INET.new(:$host, :$port);
    my @devices = "modelId.txt".IO.lines;

    my @promises = gather for @devices[159..$device-num] -> $device-id {
        take start {
            my $f = lazy $file.IO.lines;
            my $iterator = $f.iterator;

            react {
                whenever Supply.interval($interval) {
                    try {
                        my $line := $iterator.pull-one;

                        if $line =:= IterationEnd {
                            done;
                        } else {
                            my $blob = deal-data($line.chomp.split(/\s+/).tail, $device-id.Str);
                            #say $blob;
                            $conn.write($blob);
                        }
                    }

                    QUIT {
                        $conn.close;
                        say 'connecting closed';
                        default {
                            say .^name, '→ ', .Str;
                            say "handled in line $?LINE";
                        }
                    }
                    LAST {
                        say "Connection closed";
                        done;
                    }
                }
            }
        }
    }
    await @promises;
}

When running on CentOS 7.4(12 core, 32G RAM), after a few seconds, my script was killed by system. When running on Win11(12 core, 16G RAM), it's OK.

So how to debug this script?