Kevin Tse

Also, it seems like some internal ReadingService [cannot be deep-copied](https://fburl.com/testinfra/935swgsk). One alternative is for users to pass in a constructor instead of the object itself, but that will change the...

@nivekt has imported this pull request. If you are a Facebook employee, you can view this diff [on Phabricator](https://www.internalfb.com/diff/D38868731).

@nivekt has imported this pull request. If you are a Facebook employee, you can view this diff [on Phabricator](https://www.internalfb.com/diff/D38868731).

@nivekt has imported this pull request. If you are a Facebook employee, you can view this diff [on Phabricator](https://www.internalfb.com/diff/D38868731).

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> In order to fix this problem, we have to find a way to extend the existing `IterDataPipe` with all functional APIs rather than re-defining a new `IterDataPipe` in the...

I think the solution might be: 1. Call `finalize_iteration` within `DataLoader2`'s `__iter__` or `DataLoader2Iterator`'s `__init__` to ensure that, if there is an existing RS reading through, that gets terminated properly...

Agree with that.

> hopefully there will already be a nice canonical way to compose a few datapipes to achieve what they want to do #757 might allow users to more easily use...

That's a valid concern. I believe if the function is stateless (i.e. the next output only depends on the next input) then it is fine. Otherwise, it will have to...