// Create report downloader.
ReportDownloader reportDownloader = new ReportDownloader(reportService, reportJob.getId());
// Wait for the report to be ready.
reportDownloader.waitForReportReady();
// Change to your file location.
String filePath = File.createTempFile("merged-delivery-report-", ".csv.gz").toString();
System.out.printf("Downloading report to %s ...", filePath);