Azure CLI azure-devops: az artifacts universal download to network share reports success but intermittently writes file with all zero byte content.

Below is a repro of az artifacts universal download that intermittently writes all zero byte file which is expected to have non-zero byte content.

Of particular note and maybe related to the problem:

- File length is exactly 4194816 bytes = 4096.5 KB (exact power of two)
- .vmgs file is Hyper-V file, first 256+ bytes of file content are all zero bytes (in case that may confuse some check?)
- Intermittent problem seems to occur when saving to network share; do not see problem when saving to local drive (C:, D:, E:).
- Problem NOT seen when downloading other files in the same universal feed package (larger VHD files and such).
- Main problem is artifacttool.exe always reports SUCCESS whether content is incorrectly saved as all zero bytes or correctly with non-zero bytes.
-

az version

```
{
"azure-cli": "2.45.0",
"azure-cli-core": "2.45.0",
"azure-cli-telemetry": "1.0.8",
"extensions": {
"azure-devops": "0.26.0"
}
}

```
```
function CountBytes
{
[OutputType([int[]])]
param
(
[byte[]]$bytes
)

$count = [int[]]::new(256)
foreach ($byte in $bytes)
{
$count[$byte]++
}
$count
}

#$destination = "D:\ArcA\arca.onenode.complete\23.307.10327.test"
$destination = "\\N35R0403-CL\ClusterStorage$\Infrastructure_1\Downloads\arca.onenode.complete\23.307.10327.test"

$results = @()

for ($n = 1; $n -le 10; $n++)
{
[void](Remove-Item -Path $destination -Recurse -Force)
[void](New-Item -Path $destination -ItemType Directory -Force)

& az artifacts universal download --organization https://msazure.visualstudio.com/ --feed AzureStackUniversalBuddy --name arca.onenode.complete --version 23.307.10327 --path $destination --file-filter 'IRVM01/Virtual Machines/*.vmgs'
Write-Verbose -Message "LASTEXITCODE: $LASTEXITCODE" -Verbose

$file = Get-Item -Path "$destination\IRVM01\Virtual Machines\23F3E1A9-16FC-478C-B8F6-F35BACFBF989.vmgs"

Write-Verbose -Message $file -Verbose
$h = @{}
$bytes = [System.IO.File]::ReadAllBytes($file.FullName) # Get-Content -Path $vmgsFile -Encoding Byte
$count = CountBytes -bytes $bytes
$isZeros = $count[0] -eq $file.Length
if ($isZeros) { Write-Warning -Message "IsZeros: $isZeros" } else { Write-Verbose -Message "IsZeros: $isZeros" -Verbose }

$results += [PSCustomObject]@{
Attempt = $n
IsZeros = $isZeros
}
}

Write-Verbose -Message "Results:" -Verbose
$results | Format-Table -AutoSize
```

Output

```
VERBOSE: LASTEXITCODE: 0
VERBOSE: \\N35R0403-CL\ClusterStorage$\Infrastructure_1\Downloads\arca.onenode.complete\23.307.10327.test\IRVM01\Virtual Machines\23F3E1A9-16FC-478C-B8F6-F35BACFBF989.vmgs
WARNING: IsZeros: True
VERBOSE: Results:

Attempt IsZeros
------- -------
1 True
2 True
3 True
4 True
5 False
6 True
7 True
8 False
9 True
10 True
```