I have a few (breaking) ideas for improvements to the gpu_cache module functionality. But I've been thinking for a while that this doesn't really need to live here as part of rusttype. It doesn't use any non-public APIs etc, so can live as a crate on top of rusttype quite happily.

Are there some good reasons to keep it as a rusttype optional module?

Otherwise, I'd like to move it out and deprecate/eventually remove the gpu_cache feature.