presto-main/src/main/java/io/prestosql/operator/aggregation/TypedKeyValueHeap.java/TypedKeyValueHeap/getEstimatedSize
class TypedKeyValueHeap:    public long getEstimatedSize()
    {
        return INSTANCE_SIZE + keyBlockBuilder.getRetainedSizeInBytes() + valueBlockBuilder.getRetainedSizeInBytes() + sizeOf(heapIndex);
    }