CURI.pm6

    method !lazy-distribution($dist-id, :$meta) {
        class :: does Distribution::Locally {
            has $.dist-id;
            has $.read-dist;
            has $!installed-dist;
            has $.meta;
            method !dist {
                unless $!installed-dist.defined {
                    $!installed-dist = InstalledDistribution.new($.read-dist()(), :$.prefix);
                    $!meta = $!installed-dist.meta.hash;
                }
                $!installed-dist;
            }
            method meta(--> Hash:D) {
                my role LazyMetaReader {
                    has $.meta-reader;
                    method AT-KEY($key)     { $!meta-reader($key) }
                    method EXISTS-KEY($key) { ?$!meta-reader($key) }
                }
                $!meta.hash but LazyMetaReader(-> $key { $!meta{$key} // ($!meta = self!dist.meta.hash).{$key} });
            }
            method content($content-id --> IO::Handle:D) { self!dist.content($content-id) }
            method Str()                                 { self!dist.Str }
        }.new(
            :$dist-id,
            :read-dist(-> { self!read-dist($dist-id) }),
            :$meta,
            :$.prefix,
        )
    }