src/vs/platform/lifecycle/electron-main/lifecycleMainService.ts/LifecycleMainService/handleWindowUnloadVeto
class LifecycleMainService:	private handleWindowUnloadVeto(veto: boolean): boolean {
		if (!veto) {
			return false; // no veto
		}

		// a veto resolves any pending quit with veto
		this.resolvePendingQuitPromise(true /* veto */);

		// a veto resets the pending quit request flag
		this._quitRequested = false;

		return true; // veto
	}