void adding(K key, V value)
{
_keyChanged.push(F.kv(key, DictValChange <V> .add(value)));
}
void updating(K key, V oldValue, V newValue)
{
_keyChanged.push(F.kv(key, DictValChange <V> .update(oldValue, newValue)));
}
void removal(KeyValuePair <K, V> item)
{
_keyChanged.push(F.kv(item.Key, DictValChange <V> .remove(item.Value)));
}
