PrimeTweenの onCompleteが呼ばれるタイミング

結論

• startDelay

- startDelayを足した分遅れて完了が通知される

• endDelay

- endDelayを足した分遅れて完了が通知される
そりゃそう

using System;
using PrimeTween;
using UnityEngine;
using UnityEngine.UI;

public class TweenOnCompleteCheck : MonoBehaviour
{
    [SerializeField] Transform noDelay;
    [SerializeField] Transform withStartDelay;
    [SerializeField] Transform withEndDelay;
    [SerializeField] Transform withBothDelays;

    [SerializeField] float startDelayDuration = 1.0f;
    [SerializeField] float endDelayDuration = 1.0f;
    [SerializeField] float animationDuration = 4.0f;

    [SerializeField] float targetPositionX = 5.0f;

    [SerializeField] Text durationText;

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
        {
            StartTween();
        }
    }

    void StartTween()
    {
        noDelay.position = new Vector2(0, noDelay.position.y);
        withStartDelay.position = new Vector2(0, withStartDelay.position.y);
        withEndDelay.position = new Vector2(0, withEndDelay.position.y);
        withBothDelays.position = new Vector2(0, withBothDelays.position.y);

        Tween.PositionX(noDelay, targetPositionX, animationDuration, ease: Ease.Linear)
            .OnComplete(() =>
            {
                noDelay.GetComponent<SpriteRenderer>().color = Color.red;
                Debug.Log("Tween without delay completed");
            });
        Tween.PositionX(withStartDelay, targetPositionX, animationDuration, startDelay: startDelayDuration,
            ease: Ease.Linear).OnComplete(() =>
        {
            withStartDelay.GetComponent<SpriteRenderer>().color = Color.green;
            Debug.Log("Tween with start delay completed");
        });
        Tween.PositionX(withEndDelay, targetPositionX, animationDuration, endDelay: endDelayDuration,
                ease: Ease.Linear)
            .OnComplete(() =>
            {
                withEndDelay.GetComponent<SpriteRenderer>().color = Color.blue;
                Debug.Log("Tween with end delay completed");
            });
        Tween.PositionX(withBothDelays, targetPositionX, animationDuration, startDelay: startDelayDuration,
                endDelay: endDelayDuration, ease: Ease.Linear)
            .OnComplete(() =>
            {
                withBothDelays.GetComponent<SpriteRenderer>().color = Color.yellow;
                Debug.Log("Tween with both delays completed");
            });

        Tween.Custom(0f, 10f, duration: 10, onValueChange: value => durationText.text = value.ToString(), Ease.Linear);
    }
}