Begin Outputting AnnData file format

[ilan-gold]

I'm not sure if here or in pyroe this issue belongs, but I think (at least from my limited understanding), it would be cool if the sparse matrix output of alevin could be AnnData on disk. It seems like https://docs.rs/anndata/latest/anndata/ would be a good candidate for the i/o.

It seems like infer and quant would be the two candidates for them. This issue is mostly about opening a discussion about this feature, not being prescriptive or anything! I'm new to this ecosystem :)

[rob-p]

Hi @ilan-gold,

Indeed, this would be great! This would be trivial to do in pyroe, as that is in Python and has immediate access to all relevant scVerse packages.

That said, it would be cool to avoid a conversion program at all and be able to output AnnData directly (or auto convert to it if desired from within Rust). Do you know if there is an AnnData crate for rust? Otherwise, I know there’s and HDF5 crate, though that I think that pulls in the (kinda flakey?) C-based dependency.

—Rob