gRPC and pooling

I have a couple of questions regarding pooling and gRPC that I could not fully understand from existing issues or the readme. (happy to do a PR to clarify in the readme after understanding for the next person)

In https://github.com/planetscale/vtprotobuf/issues/16#issuecomment-878939364 it was mentioned, that memory-pooled objects are automatically unmarshaled using objects from a pool, which I could get to work. How is this intended to work for the other way around though? Does it happen automatically somewhere like during marshaling (if so I can't find the code that does this)? If not, is there a recommended or suggested place where this could be done (maybe in the codec?)

My use case is I have a lot of objects that I read from a key-value store that eventually end up in a gRPC response, but after marshaling the response I would like to return the objects to the pool.

Start by reading the README and the referenced issue 16 comment, then inspect the codec and generated marshaling paths mentioned in the question. Determine how pooled objects are returned after gRPC response marshaling and document the intended behavior or recommendation in the README. Verify that the documentation directly answers both pooling directions and the reported key-value-store use case.