$to->send( pack 'n/a*', $binData );

...

$from->recv( my $len, 2 );
$from->recv( my $binData, unpack 'n', $len );

##</code><code>##

use Storable qw[ freeze ];;

@a = 1..100;;

$packed = pack 'n/(n/a*)', @a;;
print length $packed;;
394

$ice = freeze \@a;;
print length $ice;;
412

@b = unpack 'n/(n/a*)', $packed;;
print "@b";;
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 ...

%h = 'aaaa'..'aaaz';;
$packed = pack 'n/(n/a*)', %h;;
print length $packed;;
158

$ice = freeze \%h;;
print length $ice;;
202

%h2 = unpack 'n/(n/a*)', $packed;;
pp \%h2;;
{
  aaaa => "aaab",
  aaac => "aaad",
  aaae => "aaaf",
  aaag => "aaah",
  aaai => "aaaj",
  aaak => "aaal",
  aaam => "aaan",
  aaao => "aaap",
  aaaq => "aaar",
  aaas => "aaat",
  aaau => "aaav",
  aaaw => "aaax",
  aaay => "aaaz",
}