---
perl: |
  use Compress::Zlib;
  %params = (
      filter_store_key => \&my_compress,
      filter_store_value => \&my_compress,
      filter_fetch_key => \&my_decompress,
      filter_fetch_value => \&my_decompress,
  );
  sub my_compress {
      my $s = shift;
      utf8::encode($s);
      return Compress::Zlib::memGzip( $s ) ;
  }
  sub my_decompress {
      my $s = Compress::Zlib::memGunzip( shift ) ;
      utf8::decode($s);
      return $s;
  }