code: func virtualEthernetCardString(d types.BaseVirtualEthernetCard) string {
  	switch d.(type) {
  	case *types.VirtualE1000:
  		return networkInterfaceSubresourceTypeE1000
  	case *types.VirtualE1000e:
  		return networkInterfaceSubresourceTypeE1000e
  	case *types.VirtualPCNet32:
  		return networkInterfaceSubresourceTypePCNet32
  	case *types.VirtualSriovEthernetCard:
  		return networkInterfaceSubresourceTypeSriov
  	case *types.VirtualVmxnet2:
  		return networkInterfaceSubresourceTypeVmxnet2
  	case *types.VirtualVmxnet3:
  		return networkInterfaceSubresourceTypeVmxnet3
  	}
  	return networkInterfaceSubresourceTypeUnknown
  }
docs: // virtualEthernetCardString prints a string representation of the ethernet device passed in.