Weird, a blog post by Collabora about a crate by Collabora, that no longer is availabe? Well, the crate seems to be, but not the code. So, what is going on here?
Seems to be a wrapper around implementing the "index into data store"-pattern (not sure if there is a better name), but without support for removal from said data store.
From a quick glance I don't really see what this gives you that wouldn't also be quite easy with a manual implementation. And then you avoid the proc macro compile time overhead as well.