src/vs/platform/extensionManagement/node/extensionDownloader.ts/ExtensionsDownloader/constructor
class ExtensionsDownloader:	constructor(
		private readonly targetPlatform: Promise<TargetPlatform>,
		@INativeEnvironmentService environmentService: INativeEnvironmentService,
		@IFileService private readonly fileService: IFileService,
		@IExtensionGalleryService private readonly extensionGalleryService: IExtensionGalleryService,
		@IConfigurationService private readonly configurationService: IConfigurationService,
		@IProductService private readonly productService: IProductService,
		@IExtensionSignatureVerificationService private readonly extensionSignatureVerificationService: IExtensionSignatureVerificationService,
		@ILogService private readonly logService: ILogService,
	) {
		super();
		this.extensionsDownloadDir = environmentService.extensionsDownloadLocation;
		this.cache = 20; // Cache 20 downloaded VSIX files
		this.cleanUpPromise = this.cleanUp();
	}