I have really early prototype for MooseX::LazyFetch. You can have a look at it: MooseX::LazyFetch, MooseX::LazyFetch::Role, MooseX::LazyFetch::Meta::Trait::Attribute

It should be used like that:

package Test;

use Moose;
use MooseX::LazyFetch;

has id => (is=>'rw');
has x => (is=>'rw', lazy_fetch => 1);
has y => (is=>'rw', lazy_fetch => 1);
has z => (is=>'rw', lazy_fetch => 1);

around 'fetcher' => sub {
    my $orig = shift;
    my $self = shift;
    return {x=>42,y=>3.14,z=>777}; # As if it fetched it
};
1;
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Once somebody try to access x,y or z, it will call fetcher, and set all attributes that are designated for lazy fetching