Resources & Scopes — Deterministic Cleanup

RAII works beautifully in synchronous Rust: resources are released when they fall out of scope, Drop runs deterministically. In async code, the picture gets complicated.

This chapter shows why RAII breaks down in async contexts, introduces Scope and finalizers as the solution, covers the acquire_release pattern for RAII-style resource management, and concludes with Pool for reusing expensive connections.