chat / KVCache requires re-prepare of media

[davidkoski]

See also #277

Although KVCache is useful to avoid recomputing state, the full input to the VLM has to be rebuilt each time -- this includes preparing the images and video. It would be nice if we could encapsulate that state somehow.

[jolonf]

I'm writing an LLM server and I want to implement a prompt cache, but I'm having trouble with the Sendable boundary and KVCache / TokenIterator, I'm wondering if you have any suggestions?

I'm thinking ideally the KVCache needs to be stored in the ModelContainer actor or ModelContext?

[davidkoski]

@jolonf please make a new issue for this -- we can discuss.

[jolonf]

I've created an issue here: #310