[metrics-bugs] #22141 [Metrics/metrics-lib]: Deprecate `DescriptorFile` and add relevant information to `Descriptor`

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#22141: Deprecate `DescriptorFile` and add relevant information to `Descriptor`
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 Reporter:  karsten              |          Owner:  metrics-team
     Type:  enhancement          |         Status:  needs_review
 Priority:  Medium               |      Milestone:  metrics-lib 1.9.0
Component:  Metrics/metrics-lib  |        Version:
 Severity:  Normal               |     Resolution:
 Keywords:                       |  Actual Points:
Parent ID:                       |         Points:
 Reviewer:                       |        Sponsor:
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Changes (by karsten):

 * status:  needs_revision => needs_review


Comment:

 Please find my updated branch with a few tweaks.  I also just commented on
 #16225 to say that this ticket addresses some aspects of what's discussed
 there.  Regarding two suggestions made there:

  - Let's talk about switching to `Future`.  One possible benefit I see is
 that we could create such an instance and put it into the queue as soon as
 we have split a descriptor file into descriptor-sized chunks and then
 parse it in the background.  And we might not even do that now but change
 the interface to doing it in the future.  A possible drawback is that the
 interface might become a little more complicated.  I haven't tried out the
 change yet, so maybe I'm wrong.  What other aspects are there?

  - I couldn't think of a good way to avoid returning `null` in
 `getException()`, at least without `Optional` which we don't have yet.  Do
 you have any ideas?

 What do you think of the change made in this ticket more generally?  The
 commit I posted was mostly a conversation starter.  It's not too late to
 do something differently or not change anything at all if there are
 aspects I have overlooked.  Thanks!

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22141#comment:6>
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