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