the page is outdated

### Page URL

https://dart.dev/language/isolates

### Page source

https://github.com/dart-lang/site-www/blob/main/src/content/language/isolates.md

### Describe the problem

outdated, informations provided are irrelevant

### Expected fix

the real documentation

### Additional context

_No response_

### I would like to fix this problem.

- [ ] I will try and fix this problem on dart.dev.