Function called when a GameObject doesn't collide with ANYTHING

Questions & Answers
1

I want to make a function called when the GameObject is NOT colliding with ANYTHING, as opposed to stopped colliding with one other GameObject.
I’d really appreciate a response of some sort, as my questions never seem to get answered.
Basically, I wanna do this:

void OnCollisionStay()
{
    //blah blah blah
}
else
{
    //blah blah blah
}

Edit: I’d be fine and even prefer if it was a function called every frame the GameObject isn’t colliding with anything, kinda like a function called every frame that OnCollisionStay isn’t.

2

using System.Collections.Generic;
using UnityEngine;

public class CollisionDetection : MonoBehaviour
{
    private HashSet<int> collidingGameObjects = new HashSet<int>();

    private void OnCollisionEnter( Collision collision )
    {
        collidingGameObjects.Add( collision.gameObject.GetInstanceID() );
    }

    private void OnCollisionExit( Collision collision )
    {
        collidingGameObjects.Remove( collision.gameObject.GetInstanceID() );
    }

    private void OnDisable()
    {
        collidingGameObjects.Clear();
    }

    private void Update()
    {
        if( collidingGameObjects.Count == 0 )
        {
            Debug.Log( "I am not colliding with anything" );
        }
    }
}