code: func isNasVolume(t types.HostFileSystemVolumeFileSystemType) bool {
  	switch t {
  	case types.HostFileSystemVolumeFileSystemTypeNFS, types.HostFileSystemVolumeFileSystemTypeNFS41:
  		return true
  	}
  	return false
  }
docs: // isNasVolume returns true if the HostFileSystemVolumeFileSystemType matches
  // one of the possible filesystem types that a NAS datastore supports.