viewmodel-input-stream.kt

class SomeViewModel(val inputStream: Observable<SomeDataType>, ...) {
private val viewState = MutableLiveData<ViewState>()
  
init {
  doStep1()
  //...
  .doStepK()
  .zipWith(inputStream) // combine/ merge 2 streams into 1 using Pair
  .map { pair ->
        val stepKresult = pair.first
        val input = pair.second // data from button click
        someUsefulVariable = ... // derived from stepKresult and button click data
        return@map processData(stepKResult, someUsefulVariable)
       }
  .handleResult { finalResult -> viewState.value = ViewState.DataLoaded(...) }
}