如何压缩(s1,o1),其中s1只发生一次,o1发生多次?

假设s1和o1完成时我需要做,但s1只发生一次,o1发生多次,每次o1发生时我都需要做一些事情。我该怎么做?

我尝试了以下代码,

val s1 = Single.fromCallable {
    Log.d("so","executing s1");
    "hello";
}.cache();

var emitter:ObservableEmitter<String>? = null;
val o1 = Observable.create<String> {
    emitter = it;
}

Observable.zip(s1.toObservable(),o1,
        BiFunction<String, String, Array<String>>() { t1, t2 -> arrayOf(t1,t2); })
        .subscribe { t1 ->
            Log.d("so", "Result = " + t1.joinToString(","));
        }

emitter?.onNext("homer");
emitter?.onNext("marge");
emitter?.onNext("bart");
Log.d("so", "Done");

但结果是

executing s1,
Result = hello,homer
Done

当我预期的结果是

executing s1,
Result = hello,homer
Result = hello,marge
Result = hello,bart
Done