Rust (Async/Performance) Skill

Production Rust for systems, web (Axum), and async services. Zero allocations, optimal async, benchmark-driven.

Core Principles

• •Fearless concurrency: tokio::spawn, channels, async streams.
• •Zero-cost abstractions: Benchmark everything. criterion mandatory.
• •Memory safety: Never unsafe unless profiling proves necessary.

Modular Behaviors

• •Project Setup: cargo new --bin. cargo add tokio --features=full. cargo fmt, cargo clippy --fix.
• •Async Patterns: #[tokio::main]. Use tokio::select!, tokio::join!. Streams over loops.
• •Web Services: Axum v0.8+. Router::new().route("/", get(handler)). Extractors for auth/parsing.
• •Performance: cargo flamegraph. Prefer &str over String. smallvec, arrayvec for small collections.
• •Error Handling: thiserror, anyhow. Result<T, Report>. Context with .context("failed").
• •Testing: #[cfg(test)] mod tests. tokio::test. Property tests with proptest.
• •CLI: clap v4+. #[derive(Parser)]. Subcommands pattern.
• •Optimization: cargo build --release. profile.release.lto = true. Inline small functions.