title: onSuccessTask vs addOnSuccessListener?
body: <p>I'm using <a href="https://firebase.google.com/docs/firestore/manage-data/add-data" rel="nofollow noreferrer">Google Firestore</a> for by Android database and want to know the different between <code>onSuccessTask</code> and <code>addOnSuccessListener</code>. </p>
  
  <p>For example, here is me updating a Firestore document:</p>
  
  <pre><code>val doc = db.collection("books").document(book).update(data)
  </code></pre>
  
  <p>For the above, to take action when the update completes,  I can do either:</p>
  
  <pre><code>.onSuccessTask { } or .addOnSuccessListener { }
  </code></pre>
  
  <p>which to me, yields the exact same result. </p>
  
  <p>Can someone clear up what the difference is and which one should be used?</p>