function Test-HyperVFeatureEnabled {
  return ((Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V).State -eq 'Enabled')
}

# After this function returns, the computer must be restarted to complete
# the installation!
function Enable-HyperVFeature {
  Log-Output "Enabling Windows 'HyperV' feature"
  Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All -NoRestart