src/vs/platform/download/common/downloadIpc.ts/DownloadServiceChannel/call
class DownloadServiceChannel:	call(context: any, command: string, args?: any): Promise<any> {
		switch (command) {
			case 'download': return this.service.download(URI.revive(args[0]), URI.revive(args[1]));
		}
		throw new Error('Invalid call');
	}