title: when does getItemCount() method get called in RecycleView adapter?
body: <p>I have a adapter which populates data to <code>RecyclerView</code>.</p>
  
  <p>I am not calling <code>notifyDataSetChanged()</code> and I am setting the adapter to the <code>RecyclerView</code> in <code>onCreateView()</code> (so in <code>getItemCount()</code> should be called once)  in Fragment but I find <code>getItemCount()</code> called multiple times.</p>