High-performance cache policies and supporting data structures.
Use //! and follow this order:
Use /// with a one-sentence summary. Mention invariants or complexity only when
they matter. Avoid Args/Returns sections unless behavior is non-obvious.
//! ## Architecture
//! ...
//!
//! ## Key Components
//! ...
//!
//! ## Core Operations
//! ...
//!
//! ## Performance Trade-offs
//! ...
//!
//! ## When to Use
//! ...
//!
//! ## Example Usage
//! ```rust
//! // ...
//! ```
//!
//! ## Type Constraints
//! ...
//!
//! ## Thread Safety
//! ...
//!
//! ## Implementation Notes
//! ...
///
/// Brief summary of behavior.