title: How can I dim the background when Bottomsheet is displayed, without using Dialog?
body: <p>I know <code>BottomSheetDialog</code> does so already, but I need to use the regular <code>BottomSheet</code> and behavior generated from <code>BottomSheetBehavior.from()</code>. This <code>BottomSheet</code> doesn't dim the background and also touch outside would not close it. Is there a way to dim the background when <code>BottomSheet</code> is displayed? and maybe dismiss when touch outside. Basically the behavior just like <code>BottomSheetDialog</code> but I must use <code>BottomSheet</code> <code>BottomSheetBehavior</code> directly.</p>