What is the second 'invalidate' argument to Readable.subscribe?

[samal-rasmussen]

The docs only say: invalidate cleanup callback. Not very informative.
https://svelte.dev/docs/svelte-store#types-readable

Anyone got a little bit more info on this? Maybe a tiny example?

[samal-rasmussen]

Got a super high quality answer on StackOverflow: https://stackoverflow.com/questions/76915395/what-is-the-second-invalidate-argument-to-readable-subscribe