withChange method
Implementation
IMap<K, V> withChange(ChangeEvent<K, V> e) => switch (e) {
KeyChanges(changes: var changes) => changes.entries.fold(
this,
(c, change) => switch (change.value) {
ChangeRecordValue(value: var v) => c.add(change.key, v),
ChangeRecordDelete() => c.remove(change.key),
}),
ChangeEventReplace(newCollection: var c) => c,
};