filterWithIndex method
Implementation
Map<K, V> filterWithIndex(bool Function(V value, int index) test) => {
for (var (index, MapEntry(:key, :value)) in entries.indexed)
if (test(value, index)) key: value
};
Map<K, V> filterWithIndex(bool Function(V value, int index) test) => {
for (var (index, MapEntry(:key, :value)) in entries.indexed)
if (test(value, index)) key: value
};