async function saveItem(item) {
        return await await _getTableContext()
            .insert({
                id: item.id,
                name: item.name,
                balance: item.balance,
                updated_at: new Date(),
            })
            .onConflict('id')
            .merge()
            .returning('id')
    }
@param {UserItem} item
@returns {Promise<string>} item ID