Call to a member function getDefaultLanguage() on null

Problem/Motivation

After upgrade to 3.0, I can't access to any media or /admin/content/media.
Error:

Call to a member function getDefaultLanguage() on null in Drupal\flysystem_s3\Flysystem\S3->getDownloadUrl() (line 33 of modules/contrib/flysystem/src/Plugin/FlysystemUrlTrait.php).

The Plugin S3.php does not define the languageManager property, so the trait FlysystemUrlTrait is not able to execute:

public function getExternalUrl($uri) {
   ......
    $language = $this->languageManager->getDefaultLanguage();
    return Url::fromRoute('flysystem.serve', $arguments, ['absolute' => TRUE, 'language' => $language])->toString();
  }

Proposed resolution

Include property in the plugin S3.php