how to add cycle offset to animation using script

I'm new in unity. Recently, I am working on a project that we need to use cycle offset as the extrapolation between given animation curve. For now, I already performed an animation I need in loop mode. But when the animation ends, it will go back to the beginning position. So I need the cycle offset to keep it moving.`empty.AddComponent(); Animation anim = empty.GetComponent(); AnimationCurve curve;

     // create a new AnimationClip
     AnimationClip clip = new AnimationClip();
     clip.legacy = true;

     // create a curve to move the GameObject and assign to the clip
     Keyframe[] keys;
     keys = new Keyframe[2];
     keys[0] = new Keyframe(0.0f, 0.0f);
     keys[1] = new Keyframe(1.0f, 1.5f);

     curve = new AnimationCurve(keys);
     clip.SetCurve("", typeof(Transform), "localPosition.z", curve);
     clip.wrapMode = WrapMode.Loop;
     
     anim.AddClip(clip, clip.name);
     
     anim.Play(clip.name);`

empty is the name of gameobject I want to move.