title: FirebaseMessagingService onMessageReceived override error
body: <p>Class:</p>
  
  <pre><code>class SubscriptionMessageService : FirebaseMessagingService() {
  
  companion object {
      private val TAG = SubscriptionMessageService::class.java.simpleName
      private const val REMOTE_MESSAGE_SUBSCRIPTIONS_KEY = "currentStatus"
  }
  
  override fun onMessageReceived(remoteMessage: RemoteMessage?) {
      remoteMessage?.data?.let {
          val data = it
          if (data.isNotEmpty()) {
              var result: List&lt;SubscriptionStatus&gt;? = null
              if (REMOTE_MESSAGE_SUBSCRIPTIONS_KEY in data) {
                  result = data[REMOTE_MESSAGE_SUBSCRIPTIONS_KEY]?.let {
                      SubscriptionStatus.listFromJsonString(it)
                  }
              }
              if (result == null) {
                  Log.e(TAG, "Invalid subscription data")
              } else {
                  val app = application as SubApp
                  app.repository.updateSubscriptionsFromNetwork(result)
              }
          }
      }
  }
  }
  </code></pre>
  
  <p>Error: 'onMessageReceived' overrides nothing</p>
  
  <p>Github Link: <a href="https://github.com/googlesamples/android-play-billing/blob/master/ClassyTaxi/android/ClassyTaxi/app/src/main/java/com/example/subscriptions/data/network/firebase/SubscriptionMessageService.kt" rel="nofollow noreferrer">https://github.com/googlesamples/android-play-billing/blob/master/ClassyTaxi/android/ClassyTaxi/app/src/main/java/com/example/subscriptions/data/network/firebase/SubscriptionMessageService.kt</a></p>