Saves the current report's export options to a memory stream.
A MemoryStream object which contains the saved export options as a byte array.
The SaveExportOptionsToMemoryStream method is intended to store export options when implementing caching for a web report.
To accomplish this task, you need to handle the ReportViewer.CacheReportDocument event, and save export options to a memory stream via the SaveExportOptionsToMemoryStream method. Then, you need to handle the ReportViewer.RestoreReportDocumentFromCache event, and restore export options via the RestoreReportDocumentFromCacheEventArgs.RestoreExportOptionsFromStream method.