title: Firestore runTransaction never runs
body: <p>I am having the strangest problem. One day, out of the blue, runTransaction simply stopped running completely. no errors. no messages. any print statements i put there never runs. nothing. like as if the runTransaction statement is not there at all.</p>
  
  <p>My code is exactly like the example code on the pub. if i just run <code>update</code> or <code>set</code> or <code>add</code> without the transaction it works perfectly.</p>
  
  <pre><code>final DocumentReference postRef = Firestore.instance.document('all_tokens/123');
  Firestore.instance.runTransaction((Transaction tx) async {
                    DocumentSnapshot postSnapshot = await tx.get(postRef);
                    if (postSnapshot.exists) {
                      await tx.update(postRef, &lt;String, dynamic&gt;{'likesCount': postSnapshot.data['likesCount'] + 1});
                    }else{
                      await tx.set(postRef, &lt;String, dynamic&gt;{'likesCount': postSnapshot.data['likesCount'] + 1});
                    }
                  });
  </code></pre>
  
  <p>No error messages at all. nothing in the <code>catch</code>, nothing in <code>then</code>. The entire thing never runs. its like its being skipped</p>
  
  <p>here is my pubspeck.yaml : </p>
  
  <pre><code>dependencies:
    flutter:
      sdk: flutter
    http: ^0.12.0
    font_awesome_flutter: ^8.2.0
    fluttertoast: ^3.0.4
    datetime_picker_formfield: ^0.1.7
    flutter_image_compress: ^0.4.0
    cloud_firestore: ^0.11.0+2
    firebase_auth: ^0.11.1
    google_sign_in: ^4.0.1+3
    firebase_messaging: ^4.0.0+3
    shared_preferences: ^0.5.2
    firebase_storage: ^3.0.0
    flutter_rating: ^0.0.2
    flutter_typeahead: ^1.4.0
    url_launcher: ^4.0.3
    flutter_facebook_login: ^2.0.0
    algolia: ^0.1.5
    geolocator: ^4.0.3
    provider: ^2.0.1
  </code></pre>