Axum Rust web framework by Tokio. Covers routing, handlers, extractors,
middleware, and state. Use for ergonomic async Rust APIs.
USE WHEN: user mentions "axum", "tokio web", "rust async api", "tower middleware",
asks about "axum extractors", "axum state", "axum router", "rust websocket axum",
"hyper server", "ergonomic rust api"
DO NOT USE FOR: Actix-web projects - use `actix-web` instead, Rocket projects - use `rocket` instead,
Warp projects - use `warp` instead, non-Rust backends