Flarum\Foundation\Application::loadDeferredProviders PHP Method

    public function loadDeferredProviders()
    {
        // We will simply spin through each of the deferred providers and register each
        // one and boot them if the application has booted. This should make each of
        // the remaining services available to this application for immediate use.
        foreach ($this->deferredServices as $service => $provider) {
            $this->loadDeferredProvider($service);
        }
        $this->deferredServices = [];
    }