src/vs/platform/policy/common/policyIpc.ts/PolicyChannelClient/constructor
class PolicyChannelClient:	constructor(policiesData: IStringDictionary<{ definition: PolicyDefinition; value: PolicyValue }>, private readonly channel: IChannel) {
		super();
		for (const name in policiesData) {
			const { definition, value } = policiesData[name];
			this.policyDefinitions[name] = definition;
			if (value !== undefined) {
				this.policies.set(name, value);
			}
		}
		this.channel.listen<object>('onDidChange')(policies => {
			for (const name in policies) {
				const value = policies[name as keyof typeof policies];

				if (value === null) {
					this.policies.delete(name);
				} else {
					this.policies.set(name, value);
				}
			}

			this._onDidChange.fire(Object.keys(policies));
		});
	}