OneStackVec is simple data structure which contains any number of items. It does not heap allocation until there is one or zero item.
```rust // Initialize let mut items = OneStackVec::new();
// Adding items.add(42);
// Getting assert_eq!(Some(&42), items.get(0));
// Removing asserteq!(Some(&42), items.remove(0)); asserteq!(None, items.get(0)); ```