title: Coroutine (WaitForSeconds()) in "OnCollisionEnter()" gives compile error
body: <p>I'm trying to make a platformer game and I want to disable gravity of platforms after x seconds. But it gives a compile error that it can't be used since <code>void</code> isn't an interior interface type.</p>
  <pre><code>private void OnCollisionEnter(Collision collision)
  {
      if (collision.gameObject.name == &quot;Platform(Clone)&quot;)
      {
          numberOfJumps = 2;
          Debug.Log(&quot;Platform hit&quot;);
      }
  
      // Make platforms fall
      yield return new WaitForSeconds(2f);
      collision.rigidbody.useGravity = enabled;
      yield return null;
  }
  </code></pre>