presto-main/src/main/java/io/prestosql/operator/aggregation/MergeQuantileDigestFunction.java/MergeQuantileDigestFunction/createInputParameterMetadata
class MergeQuantileDigestFunction:    private static List<ParameterMetadata> createInputParameterMetadata(Type valueType)
    {
        return ImmutableList.of(
                new ParameterMetadata(STATE),
                new ParameterMetadata(BLOCK_INPUT_CHANNEL, valueType),
                new ParameterMetadata(BLOCK_INDEX));
    }