self.0.borrow().iter().filter_map(move |(k, v)| f(k, &*v)).collect()
}
- /// The most interesting method: Providing a shared ref without
+ /// The most interesting method: Providing a shared reference without
/// holding the `RefCell` open, and inserting new data if the key
/// is not used yet.
/// `vacant` is called if the key is not found in the map;