wtf is wasm-parallel-gzip?

This project is a demonstration of how to run parallel file compression inside WebAssembly. Specifically, it takes a well-known command-line compression tool called pigz and compiles it into a WebAssembly module that can use multiple threads at once. The benefit is faster compression and decompression, since the work is split across several cores rather than done sequentially. At a high level, the project pulls together several pieces. It uses a special compiler toolchain to turn pigz into a WebAssembly program. It also builds a WebAssembly-compatible version of zlib, the underlying compression library pigz depends on. To actually run the resulting program, it uses Wasmtime, which is a runtime engine that supports the experimental threading feature this demo relies on. There is also an option to run it with a different engine called WAMR. The audience for this project is developers interested in the cutting edge of WebAssembly, specifically those exploring whether it can handle multi-threaded tasks normally reserved for native software. A practical scenario might be a team building a browser-based or serverless file-processing pipeline who want to speed up large file transfers by compressing them in parallel. Instead of writing a threading system from scratch, they can look at this demo to see how a real-world tool handles it. The project is explicitly a sample, not a production tool, and it relies on an experimental threading specification that is still changing. The build process is involved: it clones several external repositories as submodules and expects basic Linux tools along with Rust. The README notes there are still missing pieces in the underlying C library support, which the maintainers list as future work.