A "cursed" container with an opaque key type, that allows for retrieving mutable references to the objects contained within.
The CursedContainer is a synchronized init-on-first-use Vec<T> wrapper, where the objects
within the inner Vec are themselves contained within an [UnsafeCell], allowing for retrieval
of mutable references to those objects without a mutable reference to the CursedContainer
itself.
This design allows for assigning a CursedContainer to a static variable, like so:
```rust
static CONTAINER: CursedContainer
let key = CONTAINER.insert(69420); assert_eq!(CONTAINER.get(key), Some(&mut 69420)); ```
cursedcontainer is licensed under the MIT license, the text of which can be found in the LICENSE file, or at https://opensource.org/licenses/MIT.