public UnityFlock UnregisterRandomFlock()
    {
        if (flockBehaviors.Count == 0)
        {
            return(null);
        }
        UnityFlock removedFlock = flockBehaviors[0];

        flockTransforms.Remove(removedFlock.GetComponent <Transform>());
        flockBehaviors.RemoveAt(0);

        return(removedFlock);
    }
    public void RegisterFlock(UnityFlock flock)
    {
        if (flockBehaviors.Contains(flock))
        {
            return;
        }

        flockTransforms.Add(flock.GetComponent <Transform>());
        flockBehaviors.Add(flock);

        flock.travelOrigin = this;
        flock.origin       = this.transform;
    }