Hash attribute access that's writable

foo.raku

role IOMeta {
  my Hash %stash;
  method metadata { 
    return-rw %stash{self.path} //= Hash.new
  }
}

my $a = "foo".IO            does IOMeta;
my $b = "foo".IO.add("bar") does IOMeta;

$a.metadata<test> = 'test';
say $a.metadata;

$b.parent.metadata = %( t => 'test2');
say $a.metadata;