this blows up to 1.8gb in size after the sleep, while it is at about 0.6 before.

gistfile1.txt

#!/usr/bin/env perl6
use v6;

# This script isn't in bin/ because it's not meant to be installed.

BEGIN say 'Initializing ...';

sub recursive-dir($dir) {
    my @todo = $dir;
    gather while @todo {
        my $d = @todo.shift;
        for dir($d) -> $f {
            if $f.f {
                take $f;
            }
            else {
                @todo.push($f.path);
            }
        }
    }
}

sub MAIN() {
    say 'Reading lib/ ...';
    sleep(10); # sleep to u
    my @source  = recursive-dir('lib').grep(*.f).grep(rx{\.pod$});
       @source .= map: {; .path.subst('lib/', '').subst(rx{\.pod$}, '').subst(:g, '/', '::') => $_ };
   say @source.elems;

    sleep(10);
}