How to cache my mixture

I noticed the annotation

```python
# If you're using Seqio, we suggest caching your mixture as they take a while to generate.
```

But I don't know how to do it

Start from the Seqio caching annotation quoted in the issue and determine what steps are needed to cache a mixture. Check the repository's existing guidance for mixture generation and caching, then document a concrete workflow. Done means a user can follow the instructions to cache their mixture without needing further clarification.

Written by the indexing model from the issue text.