title: Allow BottomSheet to slide up after threshold is reached on an area outside
body: <p>I am trying to replicate a behavior that the current Google Maps has which allows the bottom sheet to be revealed when sliding up from the bottom bar.
  Notice in the recording below that I first tap on one of the buttons at the bottom bar and then slide up, which in turn reveals the sheet behind it.</p>
  
  <p><a href="https://i.stack.imgur.com/2Cl62.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2Cl62.gif" alt="enter image description here"></a></p>
  
  <p>I cannot find anywhere explained how something like this can be achieved. I tried exploring the BottomSheetBehavior and customizing it, but nowhere I can find a way to track the initial tap and then let the sheet take over the movement once the touch slop threshold is reached.</p>
  
  <p>How can I achieve this behavior without resorting to libraries? Or are there any official Google/Android views that allow this behavior between two sections (the navigation bar and bottom sheet)?</p>