TakeUntil and TakeLast Behavior

Test.kt

fun unsubsribeFirst() {
    val input = PublishSubject.create<Int>()
    val lifetime = CompletableSubject.create()

    input.ignoreElements().subscribe(lifetime)
    input.takeLast(2)
        .subscribeUntil(lifetime) { println("$it") }

    println("start")
    input.onNext(1)
    input.onNext(2)
    input.onNext(3)
    input.onComplete()
    println("end")
}

fun unsubscribeLater() {
    val input = PublishSubject.create<Int>()
    val lifetime = CompletableSubject.create()

    input.takeLast(2)
        .subscribeUntil(lifetime) { println("$it") }
    input.ignoreElements().subscribe(lifetime)

    println("start")
    input.onNext(1)
    input.onNext(2)
    input.onNext(3)
    input.onComplete()
    println("end")
}

log from unscubscribeFirst()

start
end

logs from unsubscribeLater()

start
2
3
end