presto-main/src/main/java/io/prestosql/operator/HashBuilderOperator.java/HashBuilderOperator/disposeUnspilledLookupSourceIfRequested
class HashBuilderOperator:    private void disposeUnspilledLookupSourceIfRequested()
    {
        checkState(state == State.INPUT_UNSPILLED_AND_BUILT);
        if (!spilledLookupSourceHandle.getDisposeRequested().isDone()) {
            return;
        }

        index.clear();
        localUserMemoryContext.setBytes(index.getEstimatedSize().toBytes());

        close();
    }