Azure blob download as byte array error “memory stream is not expandable”

I want to download blob as byte array, but above mention error occur. my code is as follow

Dim fullFileBytes() As Byte = {}
Dim objAzureStorage As New AzureCloudStorage

                           Dim fullImageBlob As Microsoft.WindowsAzure.Storage.Blob.CloudBlockBlob = objAzureStorage.CloudContainer.GetBlockBlobReference(row(0))

                           fullImageBlob.DownloadToByteArray(fullFileBytes, 0)