Function drop_shared 

pub unsafe fn drop_shared<T>(payload: ValuePayload)
where
    T: Clone + PartialEq + Display + Debug + Send + Sync + 'static,

Value-model re-exports: the word, its payload, type descriptors, and the export hook live in crate::value, the single representation for every type. Shared-heap drop: release one Arc strong count, freeing the buffer only when the final word drops.

Safety

The payload must co-own an Arc<T> buffer; it must never be used again afterwards.