src/vs/workbench/services/userData/browser/userDataInit.ts/UserDataInitializationService/initializeNewExtensions
class UserDataInitializationService:	private async initializeNewExtensions(instantiationService: IInstantiationService): Promise<void> {
		if (!this.initializeNewExtensionsPromise) {
			this.initializeNewExtensionsPromise = (async () => {
				this.logService.trace(`UserDataInitializationService#initializeNewExtensions`);
				const extensionsPreviewInitializer = await this.getExtensionsPreviewInitializer(instantiationService);
				if (extensionsPreviewInitializer) {
					await instantiationService.createInstance(NewExtensionsInitializer, extensionsPreviewInitializer).initialize();
				}
			})();
		}
		return this.initializeNewExtensionsPromise;
	}