title: Is it a good practice to observeForever in Repository class? db+network paged list
body: <p>Im building an app following architecture guidelines.Implemented room db caching + network.Need to get latest page number from separate entity.</p>
  
  <p>My model: </p>
  
  <pre><code>@Entity(tableName = "top_rated_movie_page")
  public class Top_Rated_Movies_Page {
  
  @PrimaryKey(autoGenerate = true)
  private int db_id;
  private Integer page;
  private Integer total_results;
  private Integer total_pages;
  @Ignore
  private List&lt;Result&gt; results;
  ...
  </code></pre>
  
  <p><code>Result</code> class contains data which i display in my paged list which observes changes from db.</p>
  
  <p>Using <code>PagedList.BoundaryCallback</code> i need to fetch new data from network and insert it into db.
  But i need to get page number somehow.
  My dao:</p>
  
  <pre><code>@Insert
  void insertAll(Top_Rated_Movies_Page page,List&lt;Result&gt; top_rated_results);
  
  @Query("SELECT * FROM Result")
  DataSource.Factory&lt;Integer, Result&gt; getAllResults();
  
  @Query("SELECT * FROM top_rated_movie_page WHERE page= (SELECT MAX(page) FROM top_rated_movie_page)")
  LiveData&lt;Top_Rated_Movies_Page&gt; getMoviePage();
  </code></pre>
  
  <p>I was thinking to observe <code>Top_Rated_Movies_Page</code> from db in my repository class with <code>observeForever()</code> to get that page number.
  Is that the best way to approach this? </p>