private IEnumerator CollectResource()
    {
        yield return(new WaitForSeconds(1.0f));

        int harvestAmount = sink.WithdrawResource(unit);

        unit.storage.amountHarvested = Mathf.Clamp(unit.storage.amountHarvested + harvestAmount, 0, unit.storage.maxHarvest);

        collectResource = null;
    }