presto-main/src/main/java/io/prestosql/operator/unnest/ReplicatedBlockBuilder.java/ReplicatedBlockBuilder/buildOutputAndFlush
class ReplicatedBlockBuilder:    public Block buildOutputAndFlush()
    {
        Block outputBlock = new DictionaryBlock(positionCount, source, ids);

        // Flush stored state, so that ids can not be modified after the dictionary has been constructed
        ids = new int[0];
        positionCount = 0;

        return outputBlock;
    }