Type Alias BoxContext 

pub type BoxContext = SmallBox<dyn Context, S4>;

Boxed context trait object using SmallBox for inline storage.

Uses SmallBox with S4 space (4 * usize = 32 bytes on 64-bit) to avoid heap allocation for small contexts (like CacheContext). Larger contexts (like CompositionContext) fall back to heap allocation automatically.

This optimization reduces allocation overhead in the common case where only basic cache context tracking is needed.

Aliased Type

pub struct BoxContext { /* private fields */ }