dispose method
void
dispose()
释放包装 Notifier 和移除 listener
Implementation
void dispose() {
_disposed = true;
// 移除所有注册的 listener
for (final remover in _listenerRemovers) {
remover();
}
_listenerRemovers.clear();
// dispose 包装的 ValueNotifier
for (final notifier in _wrappedNotifiers) {
notifier.dispose();
}
_wrappedNotifiers.clear();
}