title: Intercepting RecyclerView downwards fling in NestedScrollView
body: <p>I have the following layout:</p>
  
  <pre><code>    &lt;android.support.design.widget.CoordinatorLayout
          android:id="@+id/rootLayout"
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
  
          &lt;android.support.design.widget.AppBarLayout
              android:id="@+id/appBarLayout"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"&gt;
  
              &lt;android.support.design.widget.CollapsingToolbarLayout
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"&gt;
  
                  &lt;ImageView
                      android:layout_width="match_parent"
                      android:layout_height="160dp"
                      app:layout_collapseMode="parallax" /&gt;
  
                  &lt;android.support.v7.widget.Toolbar
                      android:layout_width="match_parent"
                      android:layout_height="52dp"
                      app:layout_collapseMode="pin" /&gt;
              &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
          &lt;/android.support.design.widget.AppBarLayout&gt;
  
          &lt;android.support.v4.widget.NestedScrollView
              android:id="@+id/nestedScrollView"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:fillViewport="true"
              app:layout_behavior="com.example.CardViewBehavior"&gt;
  
              &lt;LinearLayout
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"&gt;
  
                  &lt;FrameLayout
                      android:id="@+id/fixedBanner"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"&gt;
  
                  &lt;/FrameLayout&gt;
  
                  &lt;FrameLayout
                      android:id="@+id/card1"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"&gt;
  
                      &lt;!-- random content --&gt;
                  &lt;/FrameLayout&gt;
  
                  &lt;FrameLayout
                      android:id="@+id/card2"
                      android:layout_width="match_parent"
                      android:layout_height="match_parent"&gt;
  
                      &lt;android.support.v7.widget.RecyclerView
                          android:id="@+id/recyclerView"
                          android:layout_width="match_parent"
                          android:layout_height="match_parent" /&gt;
                  &lt;/FrameLayout&gt;
              &lt;/LinearLayout&gt;
          &lt;/android.support.v4.widget.NestedScrollView&gt;
  &lt;/layout&gt;
  </code></pre>
  
  <p>When scrolling down (finger goes upwards) from <code>fixedBanner</code> or <code>card1</code>, the <code>appBarLayout</code> collapses first, then <code>nestedScrollView</code> scrolls down. However, if scrolling down from <code>recyclerView</code>, <code>recyclerView</code> starts scrolling.  I want <code>nestedScrollView</code> to scroll down first before <code>recyclerView</code>.</p>
  
  <p>I have tried using a custom <code>CardViewBehavior</code> set on <code>nestedScrollView</code> which overrides onNestedPreScroll to consume scroll deltas if <code>appBarLayout</code> is not fully collapsed and there is still range to scroll in <code>nestedScrollView</code>.</p>
  
  <p>However, if I swipe fast enough on <code>recyclerView</code>, <code>recyclerView</code> starts flinging before <code>nestedScrollView</code> has fully scrolled to bottom.  I tried overriding <code>onNestedPreFling</code> and <code>onNestedFling</code> in <code>CardViewBehavior</code>, but it seems those two methods were never called when RecyclerView starts flinging by itself.</p>
  
  <p>How can I ensure that <code>nestedScrollView</code> scrolls to bottom before <code>recyclerView</code> starts scrolling?</p>