title: Flutter Firestore How To Listen For Changes To ONE Document
body: <p>I just want to get notified whenever ONE document is changed or updated. Every example of getting updates is always using collections. I tried to implement that with only using one document and it never gets any updates. Here is what I have right now that doesn't work:</p>
  
  <pre><code>@override
  Widget build(BuildContext context) {
  StreamBuilder&lt;DocumentSnapshot&gt;(
      stream: Firestore.instance
          .collection("users")
          .document(widget.uid)
          .snapshots(),
      builder:
          (BuildContext context, AsyncSnapshot&lt;DocumentSnapshot&gt; snapshot) {
        user = snapshot.data.data as User;
      });
  </code></pre>
  
  <p>I've debugged this 100 times and it never gets to the "builder:" section. And this is not a problem with the document reference by the way. What am I doing wrong here?</p>