semisafe_cell

A interior-mutability types that enforce runtime borrow checking in debug builds or when full_safety is enabled, otherwise the caller is reponsible for upholding Rust's aliasing rules.

Variants:

• SemiSafeCell<T>: single-threaded (uses RefCell for runtime borrow checking).
• SyncSemiSafeCell<T>: thread-safe (uses atomic_refcell::AtomicRefCell for runtime borrow checking).

Features:

• full_safety: enables runtime borrow checks in release too.
• coerce_unsized: nightly-only; allows CoerceUnsized coercions.