removeWhere method
Removes all entries of this multimap that satisfy the given predicate
.
Implementation
@override
void removeWhere(bool Function(K key, V value) predicate) {
final emptyKeys = <K>{};
// TODO(cbracken): iterate over entries
_map.forEach((K key, C values) {
_removeWhere(values, key, predicate);
if (_map[key]!.isEmpty) emptyKeys.add(key);
});
emptyKeys.forEach(_map.remove);
}