title: Offscreenpagelimit vs setItemViewCacheSize ViewPager2
body: <p>I'm using ViewPager2,
  newest version <code>'androidx.viewpager2:viewpager2:1.0.0-beta04'</code></p>
  <p>I have 10 pages and each page is Fragment.</p>
  <p>If i set <code>viewpager2.offscreenPageLimit = 1</code>
  I have to scroll to page 5 to make the first page destroy.</p>
  <p>What happened???, the first page supposed to be destroyed when I scroll to page 3 right??</p>
  <p>Then i try the other way to make it right</p>
  <pre><code>(viewpager2.getChildAt(0) as RecyclerView).layoutManager?.isItemPrefetchEnabled = false
  (viewpager2.getChildAt(0) as RecyclerView).setItemViewCacheSize(1)
  </code></pre>
  <p>This way, the first page will be destroyed when i scroll to page 3, it's working now</p>
  <p>Can anyone explain to me the differences between these 2 attributes, please?</p>