type Opt struct {
	PipeFDEnvKey              string              // needs to be set
	RunActivationHelperEnvKey string              // needs to be set
	ChildUseActivationEnvKey  string              // needs to be set
	StateDirEnvKey            string              // needs to be set
	TargetCmd                 []string            // needs to be set
	NetworkDriver             network.ChildDriver // nil for HostNetwork
	CopyUpDriver              copyup.ChildDriver  // cannot be nil if len(CopyUpDirs) != 0
	CopyUpDirs                []string
	DetachNetNS               bool
	PortDriver                port.ChildDriver
	MountProcfs               bool   // needs to be set if (and only if) parent.Opt.CreatePIDNS is set
	Propagation               string // mount propagation type
	Reaper                    bool
	EvacuateCgroup2           bool // needs to correspond to parent.Opt.EvacuateCgroup2 is set
}