Powershell script to test a domain for most common subdomains

TestForSubdomains.ps1

$serverName = "example.org"

$url = 'https://raw.githubusercontent.com/rbsec/dnscan/master/subdomains-10000.txt'

$subdomains = ((Invoke-WebRequest -Uri $url -UseBasicParsing).Content).Split("`n")
$subdomainsCount = $subdomains.Length

Write-Host ('Will test {0} entries' -f $subdomainsCount)

$count = 1

foreach ($subdomain in $subdomains)
{
    $testHost = ('{0}.{1}' -f $subdomain, $serverName)

    Write-Progress -Activity "Testing SubDomains" -Status "Test Host $testHost ($count from $subdomainsCount)" -PercentComplete (($count/$subdomainsCount)*100)

    $result = $null
    $result = Resolve-DnsName -Name $testHost -DnsOnly -Type A -ErrorAction SilentlyContinue
    if($result -ne $null)
    {
        Write-Host ('Got information about {0}' -f $testHost )
        Write-Output $result
    }

    $count ++
}

I change from sequential to parallel would have a great performance gain, but for demonstration purpose I want a simple script.