title: Flutter mobx no observable detected
body: <p>I have a MobX store which has an observable string</p>
  
  <pre><code>@observable
  String searchText = '';
  
  @action
  Future&lt;List&lt;Contact&gt;&gt; fetchContacts(int offset, String searchText) async {
  if (offset == 0) {
    _page = 1;
  }
  final response = await _contactsRepository.getAll(_page,'',{'name': searchText});
  print('offset $offset');
  _page++;
  print('response data ${response.data}');
  return response.data.isEmpty ? [] : response.data;
  </code></pre>
  
  <p>}</p>
  
  <p>In my view i am doing creating a paginated view wrapped inside of an Observer and i am using the observable string i created in the store.</p>
  
  <pre><code>SafeArea(
      child: Observer(
        builder: (_) {
          print('REBUIKD');
          return PaginationView&lt;Contact&gt;(
            separator: Divider(color: Colors.grey),
            paginationViewType: PaginationViewType.listView,
            pageFetch: (int offset) =&gt; _contactsStore.fetchContacts(
                offset, _contactsStore.searchText),
            itemBuilder: (context, Contact contact, int index) {
              return GestureDetector(
                  onTap: () =&gt; Navigator.of(context)
                      .push(MaterialPageRoute(builder: (_) {})),
                  child: ContactListItem(
                    contact: contact,
                  ));
            },
            onError: (dynamic error) =&gt; Center(
              child: Text('Some error occured'),
            ),
            onEmpty: Center(
              child: Text('Sorry! This is empty'),
            ),
            bottomLoader: Center(
              // optional
              child: CircularProgressIndicator(),
            ),
            initialLoader: Center(
              // optional
              child: CircularProgressIndicator(),
            ),
          );
        },
      ),
    ),
  </code></pre>
  
  <p>The issue is that i get the a <code>No observables detected in the build method of Observer</code> error </p>
  
  <p>The observable i want to observe to rebuild is <code>searchText</code></p>
  
  <p>I cannot understand why mobX does not detect that i am actually using the observable inside the builder</p>