Document Why the `AsyncStream` Is Not Throwing

[Frizlab]

As the stream is never-ending, if the stream ends it’s because an error occurred.

[mattmassicotte]

Do you think it would be more appropriate if it was throwing?

[Frizlab]

TL;DR: no.

Longer answer:
In general yes, because it allows getting the underlying error that made the operation fail. In this case however, our init is not throwing (it's only nullable): it makes sense to have a non-throwing iterator.
Additionally, as the stream is endless, it makes sense that if it ends, it's because it failed somehow.

Documenting this seems important though, so there is no doubt whatsoever for clients of the lib.

[mattmassicotte]

Thanks for the explanation. This makes sense!