src/vs/platform/storage/common/storage.ts/AbstractStorageService/keys
class AbstractStorageService:	keys(scope: StorageScope, target: StorageTarget): string[] {
		const keys: string[] = [];

		const keyTargets = this.getKeyTargets(scope);
		for (const key of Object.keys(keyTargets)) {
			const keyTarget = keyTargets[key];
			if (keyTarget === target) {
				keys.push(key);
			}
		}

		return keys;
	}