title: LiveData Transformation not getting triggered
body: <p>I subscribed to <code>ids</code> and <code>search</code> in the ui but i wasn't getting any results so i stepped through with the debugger and found out that the transformation is not getting triggered after the first time. So when i call <code>setIds</code> the first time <code>ids</code> gets updated but for every call after the first one the transformation won't trigger. Same goes for the <code>search</code>.</p>
  
  <p>Any ideas what might possible go wrong?</p>
  
  <pre><code>class MyViewModel : ViewModel() {
  
      private val repository = Repository.sharedInstance
  
      var recentRadius: LiveData&lt;List&lt;RecentRadius&gt;&gt;?
      var recentRoute: LiveData&lt;List&lt;RecentRoute&gt;&gt;?
  
      init {
          recentRadius = repository.recentRadius()
          recentRoute = repository.recentRoute()
      }
  
  
      private val idsInput = MutableLiveData&lt;String&gt;()
      fun setIdsInput(textId: String) {
          idsInput.value = textId
      }
  
      val ids: LiveData&lt;List&lt;String&gt;&gt; = Transformations.switchMap(idsInput) { id -&gt;
          repository.ids(id)
      }
  
      private val searchInput = MutableLiveData&lt;Search&gt;()
      fun setSearchInput(search: Search) {
          searchInput.value = search
      }
  
  
      val search: LiveData&lt;SearchResult&gt; = Transformations.switchMap(searchInput) { search -&gt;
          when (search.type) {
              SearchType.ID -&gt; repository.id(search)
              SearchType.RADIUS -&gt; repository.radius(search)
              SearchType.ROUTE -&gt; repository.route(search)
          }
      }
  }
  </code></pre>