Prefab's collider2d.bounds.size is not set

Hi.

Could you tell me when prefab's collider2d.bound.size is loaded?

I have a simple script in which I want to print prefab's size. Unfortunately size is always equal to (0.0, 0.0, 0.0) despite in editor it is equal to 170x205.

If I create new object from the same prefab in editor and then pass it to the script, size is set properly.

 using UnityEngine;
 
 public class SimpleScript : MonoBehaviour
 {
     public GameObject prefab;
 
     private void Start()
     {
         Debug.Log(string.Format("Prefab size: {0}", prefab.collider2D.bounds.size));
     }
 }