Update document

Author: jchen042

README.md

@@ -130,7 +130,7 @@ Slots are provided for rendering content dynamically. Here are slots that are id
 
 |Slot|Props|Description|
 |---|---|---|
-|fallback||There are cases when it's useful to specify fallback (i.e. default) content for a slot, to be rendered only when no content is provided.|
+|fallback||There are cases when it's useful to specify fallback (i.e. default) content for a slot, to be rendered only when no content is provided. This slot is only available when `useTimeSlicing` prop sets to `true` because it takes longer to load the content.|
 
 ## Methods
 

src/App.vue

@@ -28,7 +28,7 @@
       <virtualised-tree
         ref="treeView"
         :nodes="nodes"
-        :use-time-slicing="false"
+        :use-time-slicing="true"
         :on-change="onChange"
         :viewport-height="viewportHeight"
         :initial-scroll-top="initialScrollTop"