$ diff demo-from-doc.pl test-cache-parallel-mce.pl 
17c17
< my $c     = MCE::Shared->cache( max_keys => 500_000 );
---
> my $c     = MCE::Shared->cache();
29c29
<             for ( @{ $chunk_ref } ) { $c->set($_, {md5 => $_})  }
---
>             for ( @{ $chunk_ref } ) { $c->set($_, {md5 => $_}, 600) }