presto-spi/src/main/java/io/prestosql/spi/block/MapBlockBuilder.java/MapBlockBuilder/retainedBytesForEachPart
class MapBlockBuilder:    @Override
    public void retainedBytesForEachPart(BiConsumer<Object, Long> consumer)
    {
        consumer.accept(keyBlockBuilder, keyBlockBuilder.getRetainedSizeInBytes());
        consumer.accept(valueBlockBuilder, valueBlockBuilder.getRetainedSizeInBytes());
        consumer.accept(offsets, sizeOf(offsets));
        consumer.accept(mapIsNull, sizeOf(mapIsNull));
        consumer.accept(hashTables, hashTables.getRetainedSizeInBytes());
        consumer.accept(this, (long) INSTANCE_SIZE);
    }