Interior Mutability with RefCell

Interior Mutability with RefCell\n\nRefCell<T> enforces borrowing rules at runtime, allowing mutable borrows even when the RefCell is immutable.\n\nrust\nuse std::cell::RefCell;\n\nfn main() {\n let data = RefCell::new(vec![1, 2, 3]);\n data.borrow_mut().push(4);\n println!(\"Data: {:?}\", data.borrow());\n}\n\n