vsphere/internal/virtualdevice/virtual_machine_device_subresource.go
func (r *Subresource) GetChange(key string) (interface{}, interface{}) {
	new := r.data[key]
	// No old data means no change,  so we use the new value as a placeholder.
	old := r.data[key]
	if r.olddata != nil {
		old = r.olddata[key]
	}
	return old, new
}
func (r *Subresource) GetChange(key string) (interface{}, interface{}) {
	new := r.data[key]
	// No old data means no change,  so we use the new value as a placeholder.
	old := r.data[key]
	if r.olddata != nil {
		old = r.olddata[key]
	}
	return old, new
}
// GetChange gets the old and new values for the value specified by key.