extensions/json-language-features/client/src/node/schemaCache.ts/JSONSchemaCache/constructor
class JSONSchemaCache:	constructor(private readonly schemaCacheLocation: string, private readonly globalState: Memento) {
		const infos = globalState.get<CacheInfo>(MEMENTO_KEY, {}) as CacheInfo;
		const validated: CacheInfo = {};
		for (const schemaUri in infos) {
			const { etag, fileName, updateTime } = infos[schemaUri];
			if (typeof etag === 'string' && typeof fileName === 'string' && typeof updateTime === 'number') {
				validated[schemaUri] = { etag, fileName, updateTime };
			}
		}
		this.cacheInfo = validated;
	}