extensions/typescript-language-features/src/utils/typingsStatus.ts/AtaProgressReporter/_onBegin
class AtaProgressReporter:	private _onBegin(eventId: number): void {
		const handle = setTimeout(() => this._onEndOrTimeout(eventId), typingsInstallTimeout);
		const promise = new Promise<void>(resolve => {
			this._promises.set(eventId, () => {
				clearTimeout(handle);
				resolve();
			});
		});

		vscode.window.withProgress({
			location: vscode.ProgressLocation.Window,
			title: localize('installingPackages', "Fetching data for better TypeScript IntelliSense")
		}, () => promise);
	}