type Opt struct {
	PipeFDEnvKey    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
	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
}