forEachKey method
Applies f to each {key, Iterable<value>} pair of the multimap.
It is an error to add or remove keys from the map during iteration.
Implementation
void forEachKey(void f(K key, Iterable<V> value));Applies f to each {key, Iterable<value>} pair of the multimap.
It is an error to add or remove keys from the map during iteration.
void forEachKey(void f(K key, Iterable<V> value));