flow on...

FlowOn.kt

  private suspend fun method1a(longUrl: String): String {
    return impls.asSequence().asFlow().flatMapMerge(impls.size) { impl ->
      flow {
        impl.getShortUrl(longUrl)?.also {
          emit(it)
        }
      }.flowOn(Dispatchers.IO)
    }.first()
      .also { Dispatchers.IO.cancelChildren() }
  }

/**
22:56:30,517 INFO DumbImpl - running : DefaultDispatcher-worker-4
22:56:30,518 INFO NullImpl - running : DefaultDispatcher-worker-1
22:56:30,517 INFO IsgdImpl - running : DefaultDispatcher-worker-5
22:56:30,517 INFO TinyImpl - running : DefaultDispatcher-worker-7
22:56:30,529 INFO TinyImpl$getShortUrl$2 - running Dispatchers.IO : DefaultDispatcher-worker-7
22:56:30,529 INFO IsgdImpl$getShortUrl$2 - running Dispatchers.IO : DefaultDispatcher-worker-5
22:56:33,233 INFO IsgdImpl$getShortUrl$2 - ISGD network call invoked
22:56:33,238 INFO IsgdImpl$getShortUrl$2 - returning https://is.gd/EuvYes
22:56:33,244 INFO UrlShorterServiceTest$testHedging$1 - result = https://is.gd/EuvYes
*/