This PR adds insert_at(&mut self, Index, T) -> Option<T> and insert_at_slot(&mut self, u32, T) -> (Index, Option<T>) methods; these are useful for manipulating the arena by-slot and doing deserialization or other circumstances in which we need to "resurrect" a previous or future index.
This PR adds
insert_at(&mut self, Index, T) -> Option<T>andinsert_at_slot(&mut self, u32, T) -> (Index, Option<T>)methods; these are useful for manipulating the arena by-slot and doing deserialization or other circumstances in which we need to "resurrect" a previous or future index.