presto-main/src/main/java/io/prestosql/operator/GroupByIdBlock.java/GroupByIdBlock/retainedBytesForEachPart
class GroupByIdBlock:    @Override
    public void retainedBytesForEachPart(BiConsumer<Object, Long> consumer)
    {
        consumer.accept(block, block.getRetainedSizeInBytes());
        consumer.accept(this, (long) INSTANCE_SIZE);
    }