Add-Type -AssemblyName System.Runtime.WindowsRuntime

$asTaskGeneric = (
    [System.WindowsRuntimeSystemExtensions].GetMethods() | ? { 
        $_.Name -eq 'AsTask' `
        -and $_.GetParameters().Count -eq 1 `
        -and $_.GetParameters()[0].ParameterType.Name -eq 'IAsyncOperation`1'
    }
)[0]

Function Await($WinRtTask, $ResultType) {
    $asTask = $asTaskGeneric.MakeGenericMethod($ResultType)
    $netTask = $asTask.Invoke($null, @($WinRtTask))
    $netTask.Wait(-1) | Out-Null
    $netTask.Result
}

$connectionProfile = [
    Windows.Networking.Connectivity.NetworkInformation, Windows.Networking.Connectivity, ContentType = WindowsRuntime `
]::GetInternetConnectionProfile()

$tetheringManager = [
    Windows.Networking.NetworkOperators.NetworkOperatorTetheringManager, Windows.Networking.NetworkOperators, ContentType = WindowsRuntime `
]::CreateFromConnectionProfile($connectionProfile)

$status = $tetheringManager.TetheringOperationalState

if ($status -eq "On") {
    return
}

Await ($tetheringManager.StartTetheringAsync()) ([Windows.Networking.NetworkOperators.NetworkOperatorTetheringOperationResult])