Update LAB_AK_07.md (#218)
Update LAB_AK_07.md (#218)

Return a new DownloadPayload object instead of only the BlobStream.
MicrosoftLearning/20532-DevelopingMicrosoftAzureSolutions,MicrosoftLearning/20532-DevelopingMicrosoftAzureSolutions,MicrosoftLearning/20532-DevelopingMicrosoftAzureSolutions