// since we use append mode, when -[setData: forKey:] many times, space may not be enough
// try a full rewrite to make space
bool MMKV::ensureMemorySize(size_t newSize) {
    if (!isFileValid()) {
        MMKVWarning("[%s] file not valid", m_mmapID.c_str());
        return false;
    }

    if (newSize >= m_output->spaceLeft() || (m_crypter ? m_dicCrypt->empty() : m_dic->empty())) {
        // remove expired keys
        if (m_enableKeyExpire) {
            filterExpiredKeys();
        }
        // try a full rewrite to make space
        auto preparedData = m_crypter ? prepareEncode(*m_dicCrypt) : prepareEncode(*m_dic);
        return expandAndWriteBack(newSize, std::move(preparedData));
    }
    return true;
}