title: Object of type is not registered inside GetIt
body: <p>There is a state class</p>
  <pre><code>  Isolate isolate;
  
    static void runIsolate(SendPort sendPort) {
      stdout.write('isolate run');
      locator&lt;LocalStorageService&gt;().makeSalt(); // error
      ...
    }
  </code></pre>
  <p>The error arrives when I call locator()</p>
  <pre><code>E/flutter (32123): [ERROR:flutter/runtime/dart_isolate.cc(864)] Unhandled exception:
  E/flutter (32123): Exception: Object of type LocalStorageService is not registered inside GetIt
  E/flutter (32123): #0      GetIt.get (package:get_it/get_it.dart:30:9)
  E/flutter (32123): #1      GetIt.call (package:get_it/get_it.dart:41:12)
  E/flutter (32123): #2      _SignUpFormState.runIsolate (package:mysuperapp/forms/sign_up_form/sign_up_form.dart:154:12)
  </code></pre>
  <p>where LocalStorageService is described as</p>
  <pre><code>GetIt locator = GetIt();
  
  class LocalStorageService {
    static LocalStorageService _instance;
  
    static Future&lt;LocalStorageService&gt; getInstance() async {
      if (_instance == null) {
        _instance = LocalStorageService();
      }
  
      return _instance;
    }
    ...
  </code></pre>
  <p>Why the error arrives inside the static method? It works in regular function inside state class.</p>