title: None of the following functions can be called with the arguments supplied
body: <p>Here's the code:</p>
  
  <pre><code>getUsersObservable()
      .subscribeOn(Schedulers.io())
      //.observeOn(AndroidSchedulers.mainThread())
      .map { user: User -&gt;
          user.email = String.format("%s@rxjava.wtf", user.name)
          user.name = user.name!!.toUpperCase()
      }
      .subscribe(object : Observer&lt;User&gt; {
          override fun onComplete() {
          }
  
          override fun onSubscribe(d: Disposable) {
          }
  
          override fun onNext(t: User) {
          }
  
          override fun onError(e: Throwable) {
          }
      })
  </code></pre>
  
  <p>I get the following error:</p>
  
  <blockquote>
    <p>/Users/johann/Work/Dev/Kotlin/rxjava-walkthrough-kotlin/app/src/test/java/ktplay/RxKotlinPlay.kt:
    (49, 14): None of the following functions can be called with the
    arguments supplied: @CheckReturnValue @SchedulerSupport public final
    fun subscribe(p0: ((Unit) -> Unit)!): Disposable! defined in
    io.reactivex.Observable @SchedulerSupport public final fun
    subscribe(p0: Observer): Unit defined in
    io.reactivex.Observable @CheckReturnValue @SchedulerSupport public
    final fun subscribe(p0: Consumer!): Disposable! defined in
    io.reactivex.Observable</p>
  </blockquote>
  
  <p>This error occurs on the line with subscribe.</p>