src/vs/platform/policy/common/filePolicyService.ts/FilePolicyService/refresh
class FilePolicyService:	private async refresh(): Promise<void> {
		const policies = await this.read();
		const diff = keysDiff(this.policies, policies);
		this.policies = policies;

		if (diff.length > 0) {
			this._onDidChange.fire(diff);
		}
	}