Write Index into memory or Read Index from memory

[ava57r]

Hello.

C++ Faiss supports some methods for saving a index into memory.

write into IOWriter
https://github.com/facebookresearch/faiss/blob/main/faiss/index_io.h#L40
and impl VectorIOWriter https://github.com/facebookresearch/faiss/blob/main/faiss/impl/io.h#L59

read from IOReader
https://github.com/facebookresearch/faiss/blob/main/faiss/index_io.h#L61
and impl VectorIOReader
https://github.com/facebookresearch/faiss/blob/main/faiss/impl/io.h#L53

Could We add these impls into rust library?

[Enet4]

We would be well served with standard Rust APIs for writers and readers, so that an index can be written to anything implementing std::io::Write and an index can be read from anything implementing std::io::Read. I am not fully familiar with how these data structures operate, but so long as they can work with preallocated input/output buffers, it should be possible to interoperate them.