presto-main/src/main/java/io/prestosql/operator/aggregation/GenericAccumulatorFactory.java/GenericAccumulatorFactory/DistinctingAccumulator
class GenericAccumulatorFactory:        private DistinctingAccumulator(
                Accumulator accumulator,
                List<Type> inputTypes,
                List<Integer> inputs,
                Optional<Integer> maskChannel,
                Session session,
                JoinCompiler joinCompiler)
        {
            this.accumulator = requireNonNull(accumulator, "accumulator is null");
            this.maskChannel = requireNonNull(maskChannel, "maskChannel is null");

            hash = new MarkDistinctHash(session, inputTypes, Ints.toArray(inputs), Optional.empty(), joinCompiler, UpdateMemory.NOOP);
        }