Inserts a value associated with a given arena index into the map. If the map did not have this index present, None is returned. Otherwise, the value

Returns the length of the arena. ``` let mut arena = la_arena::Arena::new(); assert_eq!(arena.len(), 0); arena.alloc("foo"); assert_eq!(arena.len(),

Converts this index into the underlying [`RawIdx`].

Gets the given key's corresponding entry in the map for in-place manipulation.

Returns whether the index range is empty. ``` let mut arena = la_arena::Arena::new(); let one = arena.alloc(1); let two = arena.alloc(2); assert!(la

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Deconstructs a [`RawIdx`] into the underlying u32.

Returns a mutable reference to the value associated with the provided index if it is present.

Empties the arena, removing all contained values. ``` let mut arena = la_arena::Arena::new(); arena.alloc(1); arena.alloc(2); arena.alloc(3); assert

Returns whether the map contains a value for the specified index.

Returns an iterator over the arena’s mutable elements. ``` let mut arena = la_arena::Arena::new(); let idx1 = arena.alloc(20); assert_eq!(arena[idx1

return type `Liveliness` is a bit misleading here.. as it is more of a LaneMask

Returns the index of the next value allocated on the arena. This method should remain private to make creating invalid `Idx`s harder.

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.