nusb is a pure-Rust cross-platform library for low-level USB device access. It provides APIs for enumerating USB devices, opening them, claiming interfaces, and performing control, bulk, and interrupt transfers. The library is designed with an async-first approach while also supporting blocking usage through a custom `MaybeFuture` trait that can be waited on or awaited. Architecture is split into platform-specific backends (Linux usbfs, macOS IOKit, Windows WinUSB, WebUSB) with a common abstraction layer. Key features include zero-copy buffer allocation (Linux), hotplug event streams, fuzz testing for descriptor parsing, and high-level buffered IO adapters implementing standard `Read`/`Write` traits. The codebase is well-structured, thoroughly documented, and demonstrates high craftsmanship in areas like async transfer lifecycle management and cross-platform abstraction.