src/vs/platform/policy/common/policyIpc.ts/PolicyChannel/listen
class PolicyChannel:	listen(_: unknown, event: string): Event<any> {
		switch (event) {
			case 'onDidChange': return Event.map(
				this.service.onDidChange,
				names => names.reduce<object>((r, name) => ({ ...r, [name]: this.service.getPolicyValue(name) ?? null }), {}),
				this.disposables
			);
		}

		throw new Error(`Event not found: ${event}`);
	}