unity3d 刷新速率

using UnityEngine;
using UnityEngine.UI;

public class Text : MonoBehaviour {
    
    public Text t;
    private float rate = 2f;
    private float lastTime = 0;

    // Use this for initialization
    void Start () {

        Random.InitState(System.Guid.NewGuid().GetHashCode());
        
    }

    // Update is called once per frame
    void Update () {
        float time = Time.time;
        if(time - lastTime > rate)
        {
            lastTime = time;
            Text();
        }
    }
    

    public void Text()
    {
        int random = Random.Range(20, 60);
        t.text = random;
    }
}