3.x: Add onDropped callbacks to operators

[akarnokd]

Add onDropped callback overloads to most operators that drop items that can't be recovered by other means.

• [x] throttleLatest PR #7457
• [ ] throttleFirst (PR TBD)
• [ ] throttleLast / sample (PR TBD)
• [ ] throttleWithTimeout / debounce (PR TBD)
• [ ] onBackpressureLatest (PR TBD)
• [ ] onBackpressureBuffer (PR TBD)
  • 📓 The current overloads with Action are somewhat unhelpful, however, we'll have to add overloads in a way that avoids lambda ambiguity.

[Desislav-Petrov]

Hi - do you need any help with some of these?

[akarnokd]

@Desislav-Petrov you can have a stab at them. I won't have the time for weeks although there is no rush either.

[Desislav-Petrov]

Thanks, starting this week and will follow your PR per method strategy - I've started with throttleFirst

[Desislav-Petrov]

hi @akarnokd - i'm looking at throttleLast. From what I see, we should change the public void onNext(T t) method in the *SampleTimed class. More precisely, when we do the lazySet() we should check if a value exists there - if so we need to call the onDropped with this value as this is what we're dropping. Does this make sense?

[akarnokd]

@Desislav-Petrov lazySets have to be made getAndSet: https://github.com/ReactiveX/RxJava/blob/3.x/src/main/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableThrottleLatest.java#L130

[Desislav-Petrov]

Thx - leave this with me, will do a PR shortly.

[Desislav-Petrov]

taking a look at throttleWithTimeout / debounce next

[Desislav-Petrov]

Looking at onBackpressureLatest next