added Multithread variant for PS 5.x

Parallel.ps1

@@ -0,0 +1,34 @@
+$urls = @(
+    "www.google.de"
+    "www.amazon.de"
+    "www.github.com"
+    "www.youtube.com"
+    "www.gibtsnicht.com"
+)
+
+$start = Get-Date
+
+$urls | ForEach-Object -Parallel {
+    $reachable = Test-Connection -ComputerName $_ -Quiet
+    if($reachable){
+        Write-Host "$($_) is reachable"
+    }else {
+        Write-Host "$($_) could not be reached"
+    }
+}
+<#
+$urls | ForEach-Object {
+    $reachable = Test-Connection -ComputerName $_ -Quiet
+    if($reachable){
+        Write-Host "$($_) is reachable"
+    }else {
+        Write-Host "$($_) could not be reached"
+    }
+}
+#>
+
+$end = Get-Date
+$duration = $end - $start
+
+
+Write-Host "Laufzeit: $($duration.TotalSeconds)"