[@irevoire and another heed user discovered that you can align entry keys and values](https://github.com/meilisearch/heed/issues/198#issuecomment-3075347988) in LMDB with a little trick. We could use this to [make the SIMD operations more performant](https://dwrensha.github.io/capnproto-rust/2020/01/11/unaligned-memory-access.html). Have you benchmarked what's taking time?