storage function
The namespace for all the Storage functionality.
The returned service is initialized with a particular app which contains the project's storage location, or uses the default app if none is provided.
See: firebase.google.com/docs/reference/js/firebase.storage.
Implementation
Storage storage([App? app]) {
final jsObject =
(app != null) ? firebase.storage(app.jsObject) : firebase.storage();
return Storage.getInstance(jsObject);
}