The values of this.
The values are iterated in the order of their corresponding keys. This means that iterating keys and values in parallel will provide matching pairs of keys and values.
The returned iterable has an efficient
length method based on the
length of the map. Its Iterable.contains method is based on
Modifying the map while iterating the values may break the iteration.
Iterable<V> get values => _map.values;