title: A livedata in a viewmodel can just observed by one place?
body: <p>I have a livedata in a viewmodel.
  and i observe the livedata in a fragment, another class,</p>
  
  <p>when i change the livedata value, only the fragment can receive the notification of livedata change. not another class.</p>
  
  <p>i wonder just only one place(ex: fragment, activity etc) can observe a livedata of viewmodel?</p>