title: Android Room throws error: Deletion methods must either return void or return int (the number of deleted rows)
body: <p>I'm using Android Room with RxJava</p>
  
  <pre><code>dependencies {
      implementation 'androidx.room:room-rxjava2:2.1.0-alpha02'
  }
  </code></pre>
  
  <p>I need to get Completable from parameterized deletion methods, I thought this feature is added as of 2.1.0? ex.</p>
  
  <pre><code>  @Query("DELETE FROM message_table WHERE uid = :id")
    Completable delete(String id);
  
    @Query("DELETE FROM message_table")
    Completable deleteAll();
  </code></pre>
  
  <p>Still throws error: <code>Deletion methods must either return void or return int (the number of deleted rows).</code></p>