code: func NewMemoryGroupService(conf *config.Config) *MemoryGroupService {
  	memoryOnce.Do(func() {
  		memoryGroups = make(map[string]*MemoryGroup)
  		go groupTTLCleanup(conf)
  	})
  	return &MemoryGroupService{}
  }
docs: // NewMemoryGroupService returns a new group instance