What makes Postgraphile middleware's `release` method experimental?
### Summary

I was looking for a way to spin down a postgraphile instance without spinning down the entire server, and I found the `release` method declared in the interfaces.ts file, but it's labeled "experimental": https://github.com/graphile/postgraphile/blob/v4/src/interfaces.ts#L382-L383

I am hesitant to use it if it leaves Postgres connections open or is incompatible with configuration options that I need.

### Additional context

[I asked in Discord about this](https://discord.com/channels/489127045289476126/498852330754801666/964721638933426176), and was asked to turn this into an issue because it'll likely take some time to figure out what the restrictions are.