title: How to toggle a snackbar with a message coming from a ViewModel using an observer created from a fragment
body: <p><code>viewModel</code> is provided by the <code>MainActivity</code> that calls a fragment delegated to create this observer of a <code>msg</code> inside <code>onViewCreated</code></p>
  
  <pre><code>viewModel.msg.observe(requireActivity(), Observer {
              if(it.isNotEmpty() &amp;&amp; !it.isNullOrBlank()) {
                  Snackbar.make(requireView().rootView, it, Snackbar.LENGTH_SHORT)
                  viewModel.onShowMsgComplete()
              }
          })
  </code></pre>
  
  <p>The <code>msg</code> is correctly received inside the observer, but the snackbar is not showing.</p>