Debounce doesn't deliver last call to update

[yood]

Debounce seems to deliver the first skipped call to update, instead of the last call to update.

I think this happens because the skipped calls to update are scheduled to be evaluated again 1) without previous skipped calls being cancelled, and 2) are scheduled to be evaluated again very close to each other temporally. Observable.delay uses DispatchQueue.asyncAfter which isn't very precise, so whichever one fires first (usually the first one scheduled in my search-as-you-type use case) will set the new lastCalled value and ignore the others.

// skip result if there was a newer result
if currentTime.compare(lastCalled!) == .orderedDescending {
    let s = Observable<T>()
    s.delay(seconds - timeSinceLastCall!).subscribe(updateIfNeeded(observable))
    s.update(value)
}