// constructor argument should be 2 * numInputs. But for one obscure
// case we don't want to pay the penalty all the time.
: new InternalCachedBag(numInputs-1);
}
// For last bag, we always use NonSpillableBag.
dbs[lastBagIndex] = new NonSpillableDataBag((int)chunkSize);
//For each Nullable tuple in the input, put it
//into the corresponding bag based on the index,
// except for the last input, which we will stream
// The tuples will arrive in the order of the index,