src/vs/workbench/contrib/notebook/browser/notebookServiceImpl.ts/NotebookService/canResolve
class NotebookService:	async canResolve(viewType: string): Promise<boolean> {
		await this._extensionService.activateByEvent(`onNotebook:*`);

		if (!this._notebookProviders.has(viewType)) {
			await this._extensionService.whenInstalledExtensionsRegistered();
			// this awaits full activation of all matching extensions
			await this._extensionService.activateByEvent(`onNotebook:${viewType}`);
		}
		return this._notebookProviders.has(viewType);
	}