Support reading records in roaringbitmap from iteratively serialized persistent files

[KeeProMise]

Is your feature request related to a problem? Please describe.
When we serialize a roaringbitmap to disk, we should design a method of iteratively reading records from disk, so that we don't have to read all the records at once, which is more friendly to memory.

Describe the solution you'd like
You can design a new class called diskroaringbitmap, or roaringbitmapreader, or directly add a method of iteratively reading records from disk files to the existing roaringbitmap.

Please note that this is a community-based project. Consider proposing a fix (code, documentation) as a pull request.

[larsk-db]

Sounds like this is what you are looking for? https://github.com/RoaringBitmap/RoaringBitmap#working-with-memory-mapped-bitmaps

[lemire]

@larsk-db is correct... what you are probably looking for are memory-mapped bitmaps.