RFC: switch from liblzma C bindings to pure-Rust lzma-rust2 ?

[decathorpe]

I am wondering whether it would be possible (or desirable?) to replace the liblzma dependency (Rust bindings for liblzma / xz) with the lzma-rust2 crate?

The latter is a "pure Rust" port of the "xz-java" project and even seems to have performance comparable to liblzma (or better). It also avoids having to link and / or build native C code / libraries, which should make some uses cases (like cross-compilation) easier. It's also almost entirely "safe" Rust code (except for some handwritten Assembly routines, which can even be disabled).

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For context: I maintain the RPM package for the async-compression crate in Fedora Linux. The liblzma / liblzma-sys crates (forked from xz2 / lzma-sys?) would be something new to re-review / re-audit before they can be added, whereas lzma-rust2 was already added to support the zip crate.

[NobodyXu]

I would fully support that, we can initially start with following features

lzma = ["lzma-c"] # default to existing one
lzma-c = ...
lzma-rust = ...

Then we can switch the default to rust version later