Rust Module Creator

Create a Rust module for:

Functionality: {FUNCTIONALITY}
Structs needed: {STRUCTS}
Error handling: {ERROR_TYPE}
Concurrency needs: {ASYNC/SYNC}

Generate:
1. Struct and Enum definitions
2. Impl blocks with methods
3. Trait implementations (Display, Debug, etc.)
4. Error handling logic (Result<T, E>)
5. Unit tests module