Backing code to Stack Overflow PublishSubject question

PublishSubjectBehavior.kt

import io.reactivex.Observable
import io.reactivex.schedulers.Schedulers
import io.reactivex.subjects.PublishSubject
import java.util.*

// see https://stackoverflow.com/questions/44634758/unexpected-behavior-with-rxjava2-publishsubject

fun withAutoConnect() {
    val subject = PublishSubject.create<Int>()

    val o1: Observable<String> =
            subject.observeOn(Schedulers.newThread()).map { i: Int ->
                println("${Thread.currentThread()} | ${Date()} | map => $i")
                i.toString()
            }.publish().autoConnect()

    o1.subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (1) => $it")
    }

    o1.subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (2) => $it")
    }

    o1.subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (3) => $it")
    }

    println("${Thread.currentThread()} | ${Date()} | submitting 1")

    subject.onNext(1)

    Thread.sleep(1000)

    println("${Thread.currentThread()} | ${Date()} | submitting 2")

    subject.onNext(2)

    Thread.sleep(1000)

    o1.subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (4) => $it")
    }

    println("${Thread.currentThread()} | ${Date()} | submitting 3")

    subject.onNext(3)

    Thread.sleep(2000)
}

fun withOtherSubject() {
    val subject = PublishSubject.create<Int>()
    val o1 = PublishSubject.create<String>()

    subject.observeOn(Schedulers.newThread()).subscribe { i: Int ->
        println("${Thread.currentThread()} | ${Date()} | map => $i")
        o1.onNext(i.toString())
    }

    o1.observeOn(Schedulers.newThread()).subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (1) => $it")
    }

    o1.observeOn(Schedulers.newThread()).subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (2) => $it")
    }

    o1.observeOn(Schedulers.newThread()).subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (3) => $it")
    }

    println("${Thread.currentThread()} | ${Date()} | submitting 1")

    subject.onNext(1)

    Thread.sleep(1000)

    println("${Thread.currentThread()} | ${Date()} | submitting 2")

    subject.onNext(2)

    Thread.sleep(1000)

    o1.observeOn(Schedulers.newThread()).subscribe {
        println("${Thread.currentThread()} | ${Date()} | direct subscription (4) => $it")
    }

    println("${Thread.currentThread()} | ${Date()} | submitting 3")

    subject.onNext(3)

    Thread.sleep(2000)
}

fun main(args: Array<String>) {
    println("======= Auto Connect =======")
    withAutoConnect()
    println("======= Other Subject =======")
    withOtherSubject()
}